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| author | Marti Bolivar <mbolivar@leaflabs.com> | 2011-06-11 19:25:29 -0400 |
|---|---|---|
| committer | Marti Bolivar <mbolivar@leaflabs.com> | 2011-06-11 20:05:33 -0400 |
| commit | 0c2b3c667bf157dc2344e3dbc2aae0e11e37387b (patch) | |
| tree | 3008ee192c80f17f640ebdeb870442e78415ce6b /docs/source/lang/cpp | |
| parent | d4b576fcadecf66b7b754af7d204bb6f3b4a9830 (diff) | |
| download | librambutan-0c2b3c667bf157dc2344e3dbc2aae0e11e37387b.tar.gz librambutan-0c2b3c667bf157dc2344e3dbc2aae0e11e37387b.zip | |
Remove reST documentation, attendant updates.
The documentation covers topics not specifically relevant to libmaple,
so it doesn't make sense for it to be part of the libmaple source
distribution.
Delete the docs/ tree, and prepare libmaple for use with the new
leaflabs-docs repo, which will contain the docs from now on.
* README: update to reflect this change
* support/doxygen/Doxyfile: This is the old docs/Doxyfile
* Makefile: Add a doxygen target
* wirish/comm/HardwareSerial.h: fix reference to docs/. The comment
informing maintainers that the HardwareSerial interface is
documented by hand refers to the docs/ tree, which no longer exists.
Update it to refer to the separate leaflabs-docs repository.
* support/scripts/copy-to-ide: No longer build the documentation
Diffstat (limited to 'docs/source/lang/cpp')
54 files changed, 0 insertions, 3892 deletions
diff --git a/docs/source/lang/cpp/arithmetic.rst b/docs/source/lang/cpp/arithmetic.rst deleted file mode 100644 index cef3954..0000000 --- a/docs/source/lang/cpp/arithmetic.rst +++ /dev/null @@ -1,124 +0,0 @@ -.. highlight:: cpp - -.. _lang-arithmetic: - -Arithmetic Operators (``+``, ``-``, ``*``, ``/``) -================================================= - -The operators ``+``, ``-``, ``*``, and ``/`` respectively evaluate to -the sum, difference, product, or quotient (respectively) of the two -operands. The operation is conducted using the data type of the -operands, so, for example, ``9 / 4`` gives ``2`` since 9 and 4 are -:ref:`int variables <lang-int>`. - -This also means that the operation can overflow if the result is -larger than that which can be stored in the data type (e.g. adding 1 -to an :ref:`lang-int` with the value 2,147,483,647 gives --2,147,483,648). - -.. _lang-arithmetic-typeconversion: - -If the operands are of different types, the "larger" type is used for -the calculation. If one of the numbers (operands) are of the type -**float** or of type **double**, floating point math will be used for -the calculation. - -.. note:: The specifics of these rules are beyond the scope of this - documentation; for more information, see `The C++ Programming - Language <http://www2.research.att.com/~bs/3rd.html>`_\ , by Bjarne - Stroustroup, Appendix C, especially §§C.4-C.6, or `this WikiBooks - entry on C++ type conversion - <http://en.wikibooks.org/wiki/C%2B%2B_Programming/Programming_Languages/C%2B%2B/Code/Statements/Variables/Type_Casting#Automatic_type_conversion>`_. - -.. note:: For more information on how computers represent integers, - see the Wikipedia page on `two's complement - <http://en.wikipedia.org/wiki/Two's_complement>`_. - -.. contents:: Contents - :local: - -Examples --------- - - :: - - y = y + 3; - x = x - 7; - i = j * 6; - r = r / 5; - - -Syntax ------- - - :: - - result = value1 + value2; - result = value1 - value2; - result = value1 * value2; - result = value1 / value2; - - -Parameters ----------- - -**value1**: any numeric variable or constant - -**value2**: any numeric variable or constant - -Programming Tips ----------------- - -- Know that :ref:`integer constants <lang-constants-integers>` - default to :ref:`int <lang-int>`, so some constant calculations - may overflow (e.g., 200000 * 5000000 will yield a negative result). - -- Choose variable sizes that are large enough to hold the largest - results from your calculations. - -- Know at what point your variable will "roll over" and also what - happens in the other direction e.g. (0 - 1) for unsigned arithmetic, - or (0 - -2,147,483,648) for signed arithmetic. - -- For math that requires fractions, float variables may be used, but - be aware of their drawbacks: large size and slow computation speeds - (the STM32 has no floating point hardware, so all floating point - calculations have to be done in software). - -- Use cast operator, e.g. ``(int)myFloat`` to convert one variable type - to another on the fly. - -Arduino Compatibility ---------------------- - -Since the STM32 processor on the Maple is a 32-bit machine, the int -type overflows at a much higher value on Maple than on Arduino. In -particular, on Maple, ints do not overflow (become negative) until -they reach 2,147,483,648; on the Arduino, they overflow at 32,767. -Because of this, programs running on Maple are much less likely to run -into overflow issues. The following table summarizes the sizes and -ranges of integer datatypes on the Maple (the ranges of ``long long`` -types are approximate): - -.. _lang-arithmetic-int-sizes: - -.. csv-table:: - :header: Datatype, Unsigned range, Signed range, Size (bytes) - :widths: 8, 12, 17, 8 - - ``char``, 0 --- 255, -128 --- 127, 1 - ``short``, "0 --- 65,535", "-32,768 --- 32,767", 2 - ``int``, "0 --- 4,294,967,295", "-2,147,483,648 --- 2,147,483,647", 4 - ``long``, "0 --- 4,294,967,295", "-2,147,483,648 --- 2,147,483,647", 4 - ``long long``, "0 --- 1.8*10\ :sup:`19`\ " (approx.), "-9.2*10\ :sup:`18` --- 9.2*10\ :sup:`18` (approx.)", 8 - - -See Also --------- - -- The individual sizes (in bits) of various available types are - defined in :ref:`libmaple_types.h <libmaple-libmaple_types>`. - -- :ref:`sizeof <lang-sizeof>`\ () - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/array.rst b/docs/source/lang/cpp/array.rst deleted file mode 100644 index 39d4d91..0000000 --- a/docs/source/lang/cpp/array.rst +++ /dev/null @@ -1,121 +0,0 @@ -.. highlight:: cpp - -.. _lang-array: - -Arrays -====== - -An array is a collection of variables that are accessed with an index -number. Arrays in the C++ programming language, in which the Maple is -programmed, can be complicated, but using simple arrays is relatively -straightforward. - -.. contents:: Contents - :local: - -Creating (Declaring) an Array ------------------------------ - -All of the methods below are valid ways to create (declare) an -array. :: - - int myInts[6]; - int myPins[] = {2, 4, 8, 3, 6}; - int mySensVals[6] = {2, 4, -8, 3, 2}; - char message[6] = "hello"; - -You can declare an array without initializing it, as with myInts. In -the line referring to myPins, we declare an array without explicitly -choosing a size. The compiler counts the elements and creates an -array of the appropriate size. - -Finally, you can both initialize and size your array, as in -mySensVals. Note that when declaring an array with elements of type -char, one more element than your initialization is required, to hold -the required `null character <http://en.wikipedia.org/wiki/Null-terminated_string>`_. - - -Accessing an Array ------------------- - - -.. compound:: - - Arrays are **zero indexed**; that is, referring to the array - initialization above, the first element of the array is at index 0, - hence :: - - mySensVals[0] == 2; - mySensVals[1] == 4 - - and so forth. - -It also means that in an array with ten elements, index nine is the -last element. Hence:: - - int myArray[10]={9,3,2,4,3,2,7,8,9,11}; - // myArray[9] contains 11 - // myArray[10] is invalid and contains random information (other memory address) - -For this reason, you should be careful in accessing arrays. Accessing -past the end of an array (using an index number greater than your -declared array size - 1) is reading from memory that is in use for -other purposes. Reading from these locations is probably not going to -do much except yield invalid data. Writing to random memory locations -is definitely a bad idea, and can often lead to unhappy results such -as crashes or program malfunction. This can also be a difficult bug to -track down. - -Unlike Basic or Java, the C compiler does no checking to see if array -access is within legal bounds of the array size that you have -declared. - - -To assign a value to an array ------------------------------ - :: - - mySensVals[0] = 10; - - -To retrieve a value from an array ---------------------------------- - - :: - - x = mySensVals[4]; - - -Arrays and ``for`` Loops ------------------------- - -Arrays are often manipulated inside :ref:`for loops <lang-for>`, where -the loop counter is used as the index for each array element. For -example, to print the elements of an array over the serial port, you -could do something like this:: - - int i; - for (i = 0; i < 5; i = i + 1) { - SerialUSB.println(myPins[i]); - } - - -Example -------- - -For a complete program that demonstrates the use of arrays, see the -Arduino `Knight Rider example -<http://www.arduino.cc/en/Tutorial/KnightRider>`_\ (which will run -unmodified on the Maple). - -Arduino Compatibility ---------------------- - -Arrays on Maple are identical those on Arduino. - -See Also --------- - -- :ref:`Storing arrays in FLASH memory <arm-gcc-attribute-flash>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/assignment.rst b/docs/source/lang/cpp/assignment.rst deleted file mode 100644 index 6379298..0000000 --- a/docs/source/lang/cpp/assignment.rst +++ /dev/null @@ -1,60 +0,0 @@ -.. highlight:: cpp - -.. _lang-assignment: - -Assignment Operator (``=``) -=========================== - -Stores the value to the right of the equal sign in the variable to -the left of the equal sign. - -The single equal sign in the C++ programming language is called the -assignment operator. It has a different meaning than in algebra -class, where it indicated an equation or equality. The assignment -operator tells the microcontroller to evaluate whatever value or -expression is on the right side of the equal sign, and store it in -the variable to the left of the equal sign [#fgross]_. - -Example -------- - -:: - - int sensVal; // declare an integer variable named sensVal - sensVal = analogRead(0); // store the (digitized) input voltage at analog pin 0 in sensVal - -Programming Tips ----------------- - -The variable on the left side of the assignment operator (``=`` sign) -needs to be able to hold the value stored in it. If it is not large -enough to hold a value, the value stored in the variable will be -incorrect. - -Don't confuse the assignment operator ``=`` (single equal sign) with -the comparison operator ``==`` (double equal signs), which evaluates -whether two expressions are equal. - -Arduino Compatibility ---------------------- - -Assignments on the Maple are identical to those on Arduino. - -See Also --------- - -- :ref:`if <lang-if>` -- :ref:`char <lang-char>` -- :ref:`int <lang-int>` -- :ref:`long long <lang-longlong>` - -.. rubric:: Footnotes - -.. [#fgross] Experienced C++ programmers know this to be an - oversimplification of what happens when the variable on the left - hand side is an object. See Richard Gillam's wonderful and scary - `The Anatomy of the Assignment Operator - <http://icu-project.org/docs/papers/cpp_report/the_anatomy_of_the_assignment_operator.html>`_ - for more information. - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/bitshift.rst b/docs/source/lang/cpp/bitshift.rst deleted file mode 100644 index 47413f2..0000000 --- a/docs/source/lang/cpp/bitshift.rst +++ /dev/null @@ -1,143 +0,0 @@ -.. highlight:: cpp - -.. _lang-bitshift: - -Bit Shift Operators (``<<``, ``>>``) -==================================== - -(Adapted from `The Bit Math Tutorial -<http://www.arduino.cc/playground/Code/BitMath>`_ in `The Arduino -Playground <http://www.arduino.cc/playground/Main/HomePage>`_\ ) - -There are two bit shift operators in C++: the left shift operator -``<<`` and the right shift operator ``>>``. These operators cause the -bits in the left operand to be shifted left or right by the number of -positions specified by the right operand. - -More information on bitwise math can be obtained in the Wikipedia -article on `bitwise operations -<http://en.wikipedia.org/wiki/Bitwise_operation>`_\ , especially the -section on shifts in `C, C++, and Java -<http://en.wikipedia.org/wiki/Bitwise_operation#Shifts_in_C.2C_C.2B.2B.2C_C.23_and_Java>`_\ . - - -Syntax ------- - -``some_int << number_of_bits`` - -``some_int >> number_of_bits`` - - -Parameters ----------- - -* **some_int** An integer value or variable. - -* **number_of_bits** integer whose value is at most ``8 * - sizeof(variable)`` (so ``number_of_bits`` can be at most 32 for - ``int`` values, at most ``8`` for ``char`` values, etc.; the various - integer sizes are summarized :ref:`in this table - <lang-arithmetic-int-sizes>`\ ). - - - -Example: --------- - -Here are some examples of bit shifting, with the binary representation of the number in comments:: - - int a = 5; // binary: 101 - int b = a << 3; // binary: 101000, or 40 in decimal - int c = b >> 3; // binary: 101, or back to 5 like we started with - - -When you left shift a value x by y bits (x << y), the leftmost y bits -in x are lost, literally shifted out of existence. We'll do this -example with ``char`` values (which are integers in the range 0-255, -and take up 8 bits of memory):: - - char a = 5; // binary (all 8 bits): 00000101 - char b = a << 7; // binary: 10000000 - the first 1 in 101 was discarded - - -If you are certain that none of the ones in a value are being shifted -into oblivion, a simple way to think of the left-shift operator is -that it multiplies the left operand by 2 raised to the right operand -power (in math notation, ``x << y`` equals x * 2\ :sup:`y`\ , as long -as none of the bits of x get shifted out). For example, to generate -powers of 2, the following expressions can be employed:: - - 1 << 0 == 1 - 1 << 1 == 2 - 1 << 2 == 4 - 1 << 3 == 8 - ... - 1 << 8 == 256 - 1 << 9 == 512 - 1 << 10 == 1024 - ... - -.. _lang-bitshift-signbit-gotcha: - -When you shift x right by y bits (``x >> y``), and the highest bit in -x is a 1, the behavior depends on the exact data type of x. If x is of -type ``int``, the highest bit is special, and determines whether x is -negative or not; the details are too complicated to explain here, but -they are thoroughly explained in the Wikipedia article on `two's -complement arithmetic -<http://en.wikipedia.org/wiki/Two%27s_complement>`_\ , which the -system most computers use to store integers. In that case, the sign -bit is copied into lower bits, for esoteric historical reasons:: - - int x = -16; // binary (all 32 bits): 11111111111111111111111111110000 - int y = x >> 3; // binary: 11111111111111111111111111111110 - - - -This behavior, called "sign extension", is often not what you -want. You probably wish zeros to be shifted in from the left. It -turns out that the right shift rules are different for ``unsigned -int`` values, so you can use a type cast to suppress ones being copied -from the left:: - - int x = -16; // binary: 11111111111111111111111111110000 - int y = (unsigned int)x >> 3; // binary: 00011111111111111111111111111110 - - - -If you are careful to avoid sign extension, you can use the -right-shift operator, ``>>``, as a way to divide by powers of 2. For -example:: - - int x = 1000; - int y = x >> 3; // integer division of 1000 by 8, causing y = 125. - - -Arduino Compatibility ---------------------- - -Since it's part of the C++ language, bit shifting on the Maple is -compatible with the Arduino; however, you should keep in mind that the -Maple has bigger integer types (as in, more bits) than the Arduino. - -Since the STM32 is a 32-bit processor, the ``int`` type takes up 32 -bits instead of 16, like on Arduino's 16-bit microcontroller. This -means that you can shift left, like ``x << y``, with bigger values of -``y`` on the Maple before ones in ``x`` start to get shifted out. - -To calculate the number of bits of an integer type on the Maple, -multiply its size in bytes (see :ref:`this table -<lang-arithmetic-int-sizes>` for these) by 8, since there are 8 -bits in 1 byte. For example, a ``short`` takes up 2 bytes of memory, -or 2 * 8 = 16 bits. - -See Also --------- - -- :ref:`lang-bit` -- :ref:`lang-bitread` -- :ref:`lang-bitwrite` -- :ref:`lang-bitclear` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/bitwisemath.rst b/docs/source/lang/cpp/bitwisemath.rst deleted file mode 100644 index cfe34f2..0000000 --- a/docs/source/lang/cpp/bitwisemath.rst +++ /dev/null @@ -1,185 +0,0 @@ -.. highlight:: cpp - -.. _lang-bitwisemath: - -Bitwise Operators (``&``, ``|``, ``^``, ``~``) -============================================== - -The bitwise operators perform their calculations at the bit level of -variables. They help solve a wide range of common programming -problems. - -Much of the material here is adapted for Maple from an (Arduino) -`tutorial on bitwise math -<http://www.arduino.cc/playground/Code/BitMath>`_\ . Another great -resource is the Wikipedia article on `bitwise operations -<http://en.wikipedia.org/wiki/Bitwise_operation>`_\ . - -Below are descriptions and syntax for all of the operators. - -.. contents:: Contents - :local: - -.. _lang-bitwisemath-and: - -Bitwise AND (``&``) -------------------- - -The bitwise AND operator in C++ is a single ampersand, ``&``, used -between two other integer expressions. Bitwise AND operates on each -bit position of the surrounding expressions independently, according -to this rule: if both input bits are 1, the resulting output is 1, -otherwise the output is 0. Another way of expressing this is:: - - 0 0 1 1 operand1 - 0 1 0 1 operand2 - ---------- - 0 0 0 1 (operand1 & operand2) = result - - -On the Maple, the type ``int`` is a 32-bit value, so using ``&`` -between two ``int`` expressions causes 32 simultaneous AND operations -to occur. In a code fragment like:: - - int a = 92; // in binary: 00000000000000000000000001011100 - int b = 101; // in binary: 00000000000000000000000001100101 - int c = a & b; // result: 00000000000000000000000001000100, - // (or 68 in decimal). - - -Each of the 32 bits in ``a`` and ``b`` are processed using bitwise -AND, and all 32 resulting bits are stored in ``c``, resulting in the -value 1000100 in binary, which is 68 in decimal. - - -.. _lang-bitwisemath-or: - -Bitwise OR (``|``) ------------------- - -The bitwise OR operator in C++ is the vertical bar symbol, ``|``. Like -the ``&`` operator, ``|`` operates independently on each bit in its -two surrounding integer expressions, but what it does is -different. The bitwise OR of two bits is 1 if either or both of the -input bits is 1, otherwise it is 0. For example:: - - 0 0 1 1 operand1 - 0 1 0 1 operand2 - ---------- - 0 1 1 1 (operand1 | operand2) = result - -Here is an example of bitwise OR used in a snippet of C++ code (using -``char``, which takes up 8 bits of memory, instead of ``int``, which -uses 32):: - - char a = 92; // in binary: 01011100 - char b = 101; // in binary: 01100101 - char c = a | b; // result: 01111101, or 125 in decimal. - -.. _lang-bitwisemath-xor: - -Bitwise XOR (``^``) -------------------- - -There is a somewhat unusual operator in C++ called bitwise EXCLUSIVE -OR, also known as bitwise XOR. (In English, this is usually pronounced -"zor" or "ex-or"). The bitwise XOR operator is written using the caret -symbol, ``^``. This operator is very similar to the bitwise OR -operator ``|``, except it evaluates to 0 for a given bit position when -both of the input bits for that position are 1:: - - 0 0 1 1 operand1 - 0 1 0 1 operand2 - ---------- - 0 1 1 0 (operand1 ^ operand2) = result - - -Another way to look at bitwise XOR is that each bit in the result -is a 1 if the input bits are different, or 0 if they are the same. - -Here is a simple example:: - - int x = 12; // binary (ignoring extra bits): 1100 - int y = 10; // binary: 1010 - int z = x ^ y; // binary: 0110, or decimal 6 - - - -The ^ operator is often used to toggle (i.e. change from 0 to 1, or 1 -to 0) some of the bits in an integer expression. In a bitwise OR -operation if there is a 1 in the mask bit, that bit is inverted; if -there is a 0, the bit is not inverted and stays the same. Below is a -program to toggle the built-in LED pin (you can also accomplish this -with :ref:`lang-toggleled`):: - - // Toggle built-in LED pin - - int toggle = 0; - - // demo for Exclusive OR - void setup(){ - pinMode(BOARD_LED_PIN, OUTPUT); - } - - void loop(){ - toggle = toggle ^ 1; - digitalWrite(BOARD_LED_PIN, toggle); - delay(100); - } - -.. _lang-bitwisemath-not: - -Bitwise NOT (``~``) -------------------- - -The bitwise NOT operator in C++ is the tilde character ``~``. Unlike -``&`` and ``|``, the bitwise NOT operator is applied to a single -operand to its right. Bitwise NOT changes each bit to its opposite: 0 -becomes 1, and 1 becomes 0. For example:: - - 0 1 operand1 - ---- - 1 0 ~operand1 = result - -Another example:: - - char a = 103; // binary: 01100111 - char b = ~a; // binary: 10011000 = -104 - -You might be surprised to see a negative number like -104 as the -result of this operation. This is because the highest bit in an int -variable is the so-called "sign bit". If the highest bit is 1, the -number is interpreted as negative. This encoding of positive and -negative numbers is referred to as *two's complement*. For more -information, see the Wikipedia article on `two's -complement. <http://en.wikipedia.org/wiki/Twos_complement>`_ - -As an aside, it is interesting to note that (under two's complement -arithmetic) for any integer ``x``, ``~x`` is the same as ``-x-1``. - -At times, the sign bit in a signed integer expression can cause -some unwanted surprises. - - -Uses ----- - -One of the most common uses of bitwise operations is to select or -manipulate a particular bit (or bits) from an integer value, often -called `bit masking -<http://en.wikipedia.org/wiki/Mask_%28computing%29>`_\ . See the -linked Wikipedia article for more information and examples. - -If you really want to see bit-twiddling techniques in their full -glory, you could do much worse than to get yourself a copy of -`Hacker's Delight <http://www.hackersdelight.org/>`_\ . - - -See Also --------- - -- :ref:`Boolean operations <lang-boolean>` (``&&``, ``||``) -- :ref:`Compound bitwise operations <lang-compoundbitwise>` (``&=``, - ``|=``, ``^=``). - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/boolean.rst b/docs/source/lang/cpp/boolean.rst deleted file mode 100644 index f09345e..0000000 --- a/docs/source/lang/cpp/boolean.rst +++ /dev/null @@ -1,90 +0,0 @@ -.. highlight:: cpp - -.. _lang-boolean: - -Boolean Operators -================= - -These can be used inside the condition of an :ref:`if <lang-if>` -statement. Evaluate to :ref:`true <lang-constants-true>` or -:ref:`false <lang-constants-false>`. - -.. contents:: Contents - :local: - -.. _lang-boolean-and: - -&& (logical and) ----------------- - -True only if both operands are true. For example:: - - if (digitalRead(2) == HIGH && digitalRead(3) == HIGH) { // read two switches - // ... - } - -is true only if both inputs are high. Another example:: - - if (a >= 10 && a <= 20){} // true if a is between 10 and 20 - -**Be careful** not to say ``10 <= a <= 20``! This won't work the way -you want. You have to separately test whether ``a`` is at least 10 -using ``a >= 10``, then test whether ``a`` is at most 20 using ``a <= -20``, then combine the results using ``&&``. - - -.. _lang-boolean-or: - -\|\| (logical or) ------------------ - -True if either operand is true. For example:: - - if (x > 0 || y > 0) { - // ... - } - -is true if either ``x`` or ``y`` is greater than 0. - -.. _lang-boolean-not: - -! (logical not) ---------------- - -True if the operand is false. For example:: - - if (!x) { - // ... - } - -is true if ``x`` is false (i.e. if ``x`` is zero). - -Some Advice ------------ - -.. warning:: - - Make sure you don't mistake the boolean AND operator ``&&`` - (double ampersand) for the :ref:`bitwise AND operator - <lang-bitwisemath-and>` ``&`` (single ampersand). They are - entirely different beasts. - - Similarly, do not confuse the boolean OR operator ``||`` (double - pipe) with the :ref:`bitwise OR operator <lang-bitwisemath-or>` - ``|`` (single pipe). - - The :ref:`bitwise NOT operator <lang-bitwisemath-not>` ``~`` - (tilde) looks much different than the boolean not operator ``!`` - (exclamation point, or "bang", as some programmers say), but you - still have to be sure which one you want. - - -See Also --------- - -- :ref:`Bitwise operators <lang-bitwisemath>` (``&``, ``|``, ``^``, ``~``) -- :ref:`Compound bitwise operators <lang-compoundbitwise>` (``&=``, - ``|=``, ``^=``). -- :ref:`if statement <lang-if>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/booleanvariables.rst b/docs/source/lang/cpp/booleanvariables.rst deleted file mode 100644 index e032c74..0000000 --- a/docs/source/lang/cpp/booleanvariables.rst +++ /dev/null @@ -1,47 +0,0 @@ -.. highlight:: cpp - -.. _lang-booleanvariables: - -Booleans -======== - -A **boolean** holds one of two values, :ref:`true -<lang-constants-true>` or :ref:`false <lang-constants-false>`. On a -Maple, each boolean variable has type ``bool``. - -.. warning:: - - On an Arduino, the type ``boolean`` is also provided. While the - Maple also has this type for compatibility, **its use is strongly - discouraged**. The ``bool`` type is a standard part of C++, while - ``boolean`` is a non-standard extension that serves no purpose. - -Example -------- - -:: - - // running is a boolean variable: - bool running = false; - - void setup() { - pinMode(BOARD_LED_PIN, OUTPUT); - pinMode(BOARD_BUTTON_PIN, INPUT); - } - - void loop() { - if (isButtonPressed()) { - // button is pressed - running = !running; // toggle running variable - digitalWrite(BOARD_LED_PIN, running) // indicate via LED - } - } - -See Also --------- - -- :ref:`Boolean constants <lang-constants-bool>` -- :ref:`Boolean operators <lang-boolean>` -- :ref:`Variables <lang-variables>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/break.rst b/docs/source/lang/cpp/break.rst deleted file mode 100644 index f367b99..0000000 --- a/docs/source/lang/cpp/break.rst +++ /dev/null @@ -1,32 +0,0 @@ -.. highlight:: cpp - -.. _lang-break: - -``break`` -========= - -``break`` is used to exit from a :ref:`while <lang-while>`\ , -:ref:`for <lang-for>`\ , or :ref:`do/while <lang-dowhile>` loop, -bypassing the normal loop condition. It is also used to exit from a -:ref:`switch <lang-switchcase>` statement. - - -Example -------- - -:: - - for (x = 0; x < 255; x ++) - { - digitalWrite(PWMpin, x); - sens = analogRead(sensorPin); - if (sens > threshold){ // bail out on sensor detect - x = 0; - // this line of code means that we'll immediately exit - // from the "for" loop: - break; - } - delay(50); - } - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/built-in-types.rst b/docs/source/lang/cpp/built-in-types.rst deleted file mode 100644 index 28e8cdc..0000000 --- a/docs/source/lang/cpp/built-in-types.rst +++ /dev/null @@ -1,100 +0,0 @@ -.. highlight:: cpp - -.. _lang-built-in-types: - -================ - Built-in Types -================ - -This document serves as a reference for many of the built-in types -which are available when programming in the IDE. Programmers using -the :ref:`command-line tools <unix-toolchain>` will have access to -these types as long as they have imported `wirish.h -<https://github.com/leaflabs/libmaple/blob/master/wirish/wirish.h>`_; -several are defined in in `libmaple_types.h -<https://github.com/leaflabs/libmaple/blob/master/libmaple/libmaple_types.h>`_. - -.. _lang-built-in-types-integral: - -Integral types --------------- - -.. cpp:type:: char - - 8-bit integer value. - -.. cpp:type:: short - - 16-bit integer value. - -.. cpp:type:: int - - 32-bit integer value. - -.. cpp:type:: long - - 32-bit integer value. - -.. cpp:type:: long long - - 64-bit integer value. - -.. cpp:type:: int8 - - 8-bit integer value. Synonym for ``signed char``. - -.. cpp:type:: uint8 - - 8-bit unsigned integer value. Synonym for ``unsigned char``. - -.. cpp:type:: byte - - 8-bit unsigned integer value. Synonym for ``unsigned char``. - -.. cpp:type:: int16 - - 16-bit integer value. Synonym for ``short``. - -.. cpp:type:: uint16 - - 16-bit unsigned integer value. Synonym for ``unsigned short``. - -.. cpp:type:: int32 - - 32-bit integer value. Synonym for ``int``. - -.. cpp:type:: uint32 - - Unsigned 32-bit integer value. Synonym for ``unsigned int`` - -.. cpp:type:: int64 - - 64-bit integer value. Synonym for ``long long`` - -.. cpp:type:: uint64 - - Unsigned 64-bit integer value. Synonym for ``unsigned long long``. - -Floating-Point Types --------------------- - -.. cpp:type:: float - - 32-bit, IEEE-754 single-precision floating-point type. - -.. cpp:type:: double - - 64-bit, IEEE-754 double-precision floating-point type. - -Other Types ------------ - -.. cpp:type:: voidFuncPtr - - Pointer to a function that takes no arguments and returns nothing, i.e. :: - - typedef void (*voidFuncPtr)(void); - -.. cpp:type:: bool - - Boolean type. diff --git a/docs/source/lang/cpp/byte.rst b/docs/source/lang/cpp/byte.rst deleted file mode 100644 index 4634594..0000000 --- a/docs/source/lang/cpp/byte.rst +++ /dev/null @@ -1,33 +0,0 @@ -.. highlight:: cpp - -.. _lang-byte: - -byte -==== - -The ``byte`` type stores a 1-byte (8-bit) unsigned integer number, -from 0 to 255. - -.. warning:: - - The ``byte`` type is provided for compatibility with Arduino. - However, it is a non-standard extension. The standard C++ type for - storing an 8-bit unsigned integer is ``unsigned char``; we - recommend using that instead. (Your code will still work on an - Arduino). - - -Example -------- - -:: - - byte b = 134; - -See Also --------- - -- :ref:`byte() <lang-bytecast>` (casting a value to a byte) -- :ref:`Variables <lang-variables>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/bytecast.rst b/docs/source/lang/cpp/bytecast.rst deleted file mode 100644 index 24c3b9e..0000000 --- a/docs/source/lang/cpp/bytecast.rst +++ /dev/null @@ -1,44 +0,0 @@ -.. highlight:: cpp - -.. _lang-bytecast: - -byte() (cast) -============= - -Converts a value to the :ref:`byte <lang-byte>` data type. - -.. note:: - - Casting to the byte type is provided for compatibility with - Arduino. However, the recommended Maple type for storing an 8-bit - unsigned integer is ``uint8``. (C and C++ programmers: ``stdint.h`` - is also available). - - In order to cast a variable ``x`` to a ``uint8``, the - following syntax can be used:: - - uint8(x); - -Syntax ------- - -``byte(x)`` - -Parameters ----------- - -**x**: a value of any integer type - -Returns -------- - -The value, converted to a ``byte``. Note, however, that if the value -is larger than the maximum value you can store in a byte (255), then -the results might be strange and unexpected. - -See Also --------- - -- :ref:`lang-byte` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/cc-attribution.txt b/docs/source/lang/cpp/cc-attribution.txt deleted file mode 100644 index e100140..0000000 --- a/docs/source/lang/cpp/cc-attribution.txt +++ /dev/null @@ -1,9 +0,0 @@ -.. Included in all this directory's files in order to satisfy the -.. Arduino CC Attribution-ShareAlike 3.0 License - -.. admonition:: License and Attribution - - This documentation page was adapted from the `Arduino Reference - Documentation <http://arduino.cc/en/Reference/HomePage>`_\ , which - is released under a `Creative Commons Attribution-ShareAlike 3.0 - License <http://creativecommons.org/licenses/by-sa/3.0/>`_. diff --git a/docs/source/lang/cpp/char.rst b/docs/source/lang/cpp/char.rst deleted file mode 100644 index 686c0d1..0000000 --- a/docs/source/lang/cpp/char.rst +++ /dev/null @@ -1,44 +0,0 @@ -.. highlight:: cpp - -.. _lang-char: - -``char`` -======== - -The ``char`` type stores a 1-byte character value (or integer with -value from -128 to 127). Character literals are written in single -quotes, like this: ``'A'`` (for multiple characters - strings - use -double quotes: ``"ABC"``). - -Just like everything else on a computer, characters are stored as -numbers. You can see the specific encoding in the `ASCII chart -<http://en.wikipedia.org/wiki/ASCII#ASCII_printable_characters>`_\ -. This means that it is possible to do arithmetic on characters, in -which the ASCII value of the character is used (e.g. ``'A' + 1`` has the -decimal value 66, since the ASCII value of the capital letter A in -decimal is 65). See the :ref:`Serial.println() -<lang-serial-println>` documentation for more information about how -characters are converted into numbers. - -The ``char`` datatype is a signed type, meaning that it encodes -numbers from -128 to 127. For an unsigned type, which stores values -from 0 to 255, just use the type ``unsigned char`` (two words). - -Example -------- - -:: - - // The following two lines are equivalent, using the ASCII - // character encoding: - char c = 'A'; - char c = 65; - -See Also --------- - -- :ref:`lang-int` -- :ref:`lang-array` (a string is just an array of ``char``\ s) -- :ref:`Serial.println() <lang-serial-println>` - -.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/charcast.rst b/docs/source/lang/cpp/charcast.rst deleted file mode 100644 index 640ad85..0000000 --- a/docs/source/lang/cpp/charcast.rst +++ /dev/null @@ -1,32 +0,0 @@ -.. highlight:: cpp - -.. _lang-charcast: - -``char()`` (cast) -================= - -Converts a value to the :ref:`char <lang-char>` data type. - -Syntax ------- - -``char(x)`` - -Parameters ----------- - -**x**: a value of any type - -Returns -------- - -The value, converted to a ``char``. Note, however, that if the value -is outside the range of a ``char`` (-128 to 127), then the results -might be strange and unexpected. - -See Also --------- - -- :ref:`char <lang-char>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/comments.rst b/docs/source/lang/cpp/comments.rst deleted file mode 100644 index 1428dc3..0000000 --- a/docs/source/lang/cpp/comments.rst +++ /dev/null @@ -1,64 +0,0 @@ -.. highlight:: cpp - -.. _lang-comments: - -Comments -======== - -Comments are lines in the program that are used to inform yourself or -others about the way the program works. They are ignored by the -compiler, and not exported to the processor, so they don't take up any -space in RAM or Flash. - -One use for comments is to help you understand (or remember) how your -program works, or to inform others how your program works. There are -two different ways of making comments. - -.. _lang-comments-singleline: - -**Single line comment**: Anything following two slashes, ``//``, until -the end of the line, is a comment:: - - x = 5; // the rest of this line is a comment - -.. _lang-comments-multiline: - -**Multi-line comment**: Anything in between a pair of ``/*`` and ``*/`` -is a comment:: - - /* <-- a slash-star begins a multi-line comment - - all of this in the multi-line comment - you can use it to comment - out whole blocks of code - - if (gwb == 0){ // single line comment is OK inside a multi-line comment - x = 3; - } - - // don't forget the "closing" star-slash - they have to be balanced: - */ - -Note that it's okay to use single-line comments within a multi-line -comment, but you can't use multi-line comments within a multi-line -comment. Here's an example:: - - /* ok, i started a multi-line comment - - x = 3; /* this next star-slash ENDS the multi-line comment: */ - - x = 4; // this line is outside of the multi-line comment - - // next line is also outside of the comment, and causes a compile error: - */ - -Programming Tip ---------------- - -When experimenting with code, "commenting out" parts of your program -is a convenient way to remove lines that may be buggy. This leaves -the lines in the code, but turns them into comments, so the compiler -just ignores them. This can be especially useful when trying to locate -a problem, or when a program refuses to compile and the compiler error -is cryptic or unhelpful. - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/comparison.rst b/docs/source/lang/cpp/comparison.rst deleted file mode 100644 index 9cd0a9f..0000000 --- a/docs/source/lang/cpp/comparison.rst +++ /dev/null @@ -1,86 +0,0 @@ -.. highlight:: cpp - -.. _lang-comparison: - -Comparison Operators (``==``, ``!=``, ``<``, ``>``, ``<=``, ``>=``) -=================================================================== - -The comparison operators ``==``, ``!=``, ``<``, ``>``, ``<=``, and -``>=`` are used to compare two numbers. They are :ref:`true -<lang-constants-true>` when the comparison is true, and :ref:`false -<lang-constants-false>` otherwise. They are based on the symbols -=, ≠, <, >, ≤, and ≥ from mathematics. - -Here are some examples, with their meaning in comments:: - - // "eq" is true when x is equal to y - bool eq = (x == y); - - // "neq" is true when x is different than y - bool neq = (x != y); - - // "lt" is true when x is less than, but NOT equal to, y - bool lt = (x < y); - - // "gt" is true when x is greater than, but NOT equal to, y - bool gt = (x > y); - - // "lte" is true when x is less than or equal to y - bool lte = (x <= y); - - // "gte" is true when x is greater than or equal to y - bool gte = (x >= y); - -The parentheses are optional; they are present only for clarity. For -example, the following two lines are the same:: - - bool eq = x == y; - - bool eq = (x == y); - -Uses ----- - -Comparison operators, along with :ref:`boolean operators -<lang-boolean>`, are useful inside the conditionals of :ref:`if -<lang-if>` statements. Here's one example:: - - if (x < 50) { - // only execute these lines if x is less than 50 - SerialUSB.println("delaying:"); - SerialUSB.println(x); - delay(x); - } - -.. warning:: - Beware of accidentally using the single equal sign (``=``) when you - meant to test if two numbers are equal (``==``). This is a common - mistake inside of ``if`` statement conditionals, e.g.:: - - // DON'T MAKE THIS MISTAKE - if (x = 10) { - // body - } - - The single equal sign is the assignment operator, and sets x to 10 - (puts the value 10 into the variable x). Instead use the double equal - sign (e.g. ``if (x == 10)``), which is the comparison operator, and - tests *whether* x is equal to 10 or not. The latter statement is only - true if x equals 10, but the former statement will always be true. - - This is because C evaluates the statement ``if (x=10)`` as follows: 10 - is assigned to x (remember that the single equal sign is the - :ref:`assignment operator <lang-assignment>`), so x now - contains 10. Then the 'if' conditional evaluates 10, which evaluates - to :ref:`true <lang-constants-true>`, since any non-zero number - evaluates to ``true``. - - Consequently, the conditional of an ``if`` statement like ``if (x = - 10) {...}`` will always evaluate to ``true``, and the variable x - will be set to 10, which is probably not what you meant. - - (This sometimes has uses, though, so just because an assignment - appears within a conditional doesn't mean it's automatically wrong. - Be careful to know what you mean.) - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/compoundarithmetic.rst b/docs/source/lang/cpp/compoundarithmetic.rst deleted file mode 100644 index d70a43c..0000000 --- a/docs/source/lang/cpp/compoundarithmetic.rst +++ /dev/null @@ -1,43 +0,0 @@ -.. highlight:: cpp - -.. _lang-compoundarithmetic: - -Compound Arithmetic Operators (``+=`` , ``-=``, ``*=``, ``/=``) -=============================================================== - -These oparators perform a mathematical operation on a variable with -another constant or variable. These operators are just a convenient -shorthand:: - - x += y; // equivalent to the expression x = x + y; - x -= y; // equivalent to the expression x = x - y; - x *= y; // equivalent to the expression x = x * y; - x /= y; // equivalent to the expression x = x / y; - -Here is an example:: - - int x = 2; - int y = 10; - - x += 4; // x now contains 6 - x -= 3; // x now contains 3 - x *= y; // x now contains 30 - x /= 2; // x now contains 15 - x += max(20, 6); // x now contains 35 - x -= sq(5); // x now contains 15 - -Parameters ----------- - -**x**: a numeric variable - -**y**: a numeric variable, number constant, or any other expression -that evaluates to a number (e.g. call to a function that returns a -number). - -See Also --------- - -- :ref:`Arithmetic operators <lang-arithmetic>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/compoundbitwise.rst b/docs/source/lang/cpp/compoundbitwise.rst deleted file mode 100644 index 4efe5df..0000000 --- a/docs/source/lang/cpp/compoundbitwise.rst +++ /dev/null @@ -1,229 +0,0 @@ -.. highlight:: cpp - -.. _lang-compoundbitwise: - -Compound Bitwise Operators (``&=``, ``|=``, ``^=``) -=================================================== - -The compound bitwise operators perform their calculations at the -bit level of variables. They are often used to clear and set -specific bits of a variable. - -See the :ref:`bitwise math tutorial <lang-bitwisemath>` for more -information on bitwise operators. - -.. contents:: Contents - :local: - -.. _lang-compoundbitwise-and: - -Compound bitwise AND (``&=``) ------------------------------ - -The compound bitwise AND operator ``&=`` is often used with a variable -and a constant to force particular bits in a variable to be zero. This -is often referred to in programming guides as "clearing" or -"resetting" bits. In a program, writing the line ``x &= y;`` is -equivalent to writing ``x = x & y;``. That is, the value of ``x`` -after the line will be equal to its old value bitwise ANDed with the -value of ``y``:: - - x &= y; // equivalent to x = x & y; - -You can use any integer variable for ``x`` (i.e., any variable of type -``int``, ``char``, ``byte``, ``long long``, etc.). You can use either -an integer variable or any :ref:`integer value -<lang-constants-integers>` (like ``3`` or ``0x20``) for ``y``. - -Before doing an example of ``&=``, let's first review the Bitwise AND -(``&``) operator:: - - 0 0 1 1 operand1 - 0 1 0 1 operand2 - ---------- - 0 0 0 1 (operand1 & operand2) = result - -As shown above, bits that are "bitwise ANDed" with 0 become 0, while -bits that are "bitwise ANDed" with 1 are left unchanged. So, if ``b`` -is a ``byte`` variable, then ``b & B00000000`` equals zero, and ``b & -B11111111`` equals ``b``. - -.. _lang-compoundbitwise-binconst: - -.. note:: The above uses :ref:`binary constants - <lang-constants-integers-bin>`\ . The numbers are still the same - value in other representations, they just might not be as easy to - understand. - - Normally, in C and C++ code, :ref:`hexadecimal - <lang-constants-integers-hex>` or :ref:`octal - <lang-constants-integers-oct>` are used when we're interested in - an integer's bits, rather than its value as a number. - - While hexadecimal and octal literals might be harder to understand - at first, you should really take the time to learn them. They're - part of C, C++, and many other programming languages, while binary - constants are available only for compatibility with Arduino. - - Also, ``B00000000`` is shown for clarity, but zero in any number - format is zero. - -So, to clear (set to zero) bits 0 and 1 of a one-byte variable, while -leaving the rest of the variable's bits unchanged, use the compound -bitwise AND operator ``&=`` with the constant ``B11111100`` -(hexadecimal ``0xFC``\ ):: - - 1 0 1 0 1 0 1 0 variable - 1 1 1 1 1 1 0 0 mask - ---------------------- - 1 0 1 0 1 0 0 0 - ^^^^^^^^^^^^^^^^ ^^^^ - unchanged cleared - - -Here is the same representation with the variable's bits replaced -with the symbol ``x``\ :: - - x x x x x x x x variable - 1 1 1 1 1 1 0 0 mask - ---------------------- - x x x x x x 0 0 - ^^^^^^^^^^^^^^^^ ^^^^ - unchanged cleared - - -So, using a byte variable ``b``\ , if we say:: - - b = B10101010; // B10101010 == 0xAA - b &= B11111100; // B11111100 == 0xFC - -then we will have :: - - b == B10101000; // B10101000 == 0xA8 - -.. _lang-compoundbitwise-or: - -Compound bitwise OR (``|=``) ----------------------------- - -The compound bitwise OR operator ``|=`` is often used with a variable -and a constant to "set" (set to 1) particular bits in a variable. In -a program, writing the line ``x |= y;`` is equivalent to writing ``x = -x | y;``. That is, the value of ``x`` after the line will be equal to -its old value bitwise ORed with the value of ``y``:: - - x |= y; // equivalent to x = x | y; - -You can use any integer variable for ``x`` (i.e., any variable of type -``int``, ``char``, ``long long`` etc.). You can use either an integer -variable or any integer value (like ``3`` or ``0x20``) for ``y``. -(This works the same way as :ref:`compound bitwise AND -<lang-compoundbitwise-and>`\ , ``&=``). - -Before doing an example of ``|=``, let's first review the Bitwise OR -(``|``) operator:: - - 0 0 1 1 operand1 - 0 1 0 1 operand2 - ---------- - 0 1 1 1 (operand1 | operand2) = result - -Bits that are "bitwise ORed" with 0 are unchanged, while bits that are -"bitwise ORed" with 1 are set to 1. So if ``b`` is a ``byte`` -variable, then ``b | B00000000`` equals ``b``, and ``b & B11111111`` -equals ``B11111111`` (here we've used binary constants; see the -:ref:`note <lang-compoundbitwise-binconst>` above). - -So, to set bits 0 and 1 of a one-byte variable, while leaving the rest -of the variable unchanged, use the compound bitwise OR operator -(``|=``) with the constant ``B00000011`` (hexadecimal ``0x3``):: - - 1 0 1 0 1 0 1 0 variable - 0 0 0 0 0 0 1 1 mask - ---------------------- - 1 0 1 0 1 0 1 1 - ^^^^^^^^^^^^^^^^ ^^^^ - unchanged set - -Here is the same representation with the variable's bits replaced with -the symbol ``x``:: - - x x x x x x x x variable - 0 0 0 0 0 0 1 1 mask - ---------------------- - x x x x x x 1 1 - ^^^^^^^^^^^^^^^^ ^^^^ - unchanged set - -So, using a byte variable ``b``, if we say:: - - b = B10101010; // B10101010 == 0xAA - b |= B00000011; // B00000011 == 0x3 - -then we will have :: - - b == B10101011; // B10101011 == 0xAB - -.. _lang-compoundbitwise-xor: - -Compound bitwise XOR (``^=``) ------------------------------ - -The compound bitwise XOR operator ``^=`` is used with a variable and a -constant to "toggle" (change 0 to 1, and 1 to 0) particular bits in a -variable. In a program, writing the line ``x ^= y;`` is equivalent to -writing ``x = x ^ y;``. That is, the value of ``x`` after the line -will be equal to its old value bitwise XORed with the value of ``y``:: - - x ^= y; // equivalent to x = x ^ y; - -You can use any integer variable for ``x`` (i.e., any variable of type -``int``, ``char``, ``long long``, etc.). You can use either an -integer variable or any integer value (like ``3`` or ``0x20``) for -``y``. (This works the same way as :ref:`&= -<lang-compoundbitwise-and>` and :ref:`\|= <lang-compoundbitwise-or>`; -in fact, these three operators all work the same in this way). - -Before doing an example of ``^=``, let's first review the Bitwise -XOR operator, ``^``:: - - 0 0 1 1 operand1 - 0 1 0 1 operand2 - ---------- - 0 1 1 0 (operand1 ^ operand2) = result - -One way to look at bitwise XOR is that each bit in the result is a 1 -if the input bits are different, or 0 if they are the same. Another -way to think about it is that the result bit will be 1 when *exactly* -one (no more, no less) of the input bits is 1; otherwise, it will be -zero. This means that if you XOR a bit with 1, it will change (or -toggle) its value, while if you XOR a bit with 0, it stays the same. - -So, to toggle bits 0 and 1 of a one-byte variable, while leaving the -rest of the variable unchanged, use the compound bitwise XOR operator -``^=`` with the constant ``B00000011`` (hexadecimal ``0x3``\ ; see -:ref:`note <lang-compoundbitwise-binconst>` above):: - - 1 0 1 0 1 0 1 0 variable - 0 0 0 0 0 0 1 1 mask - ---------------------- - 1 0 1 0 1 0 1 1 - ^^^^^^^^^^^^^^^^ ^^^^ - unchanged toggled - -So, using a byte variable ``b``, if we say:: - - b = B10101010; // B10101010 == 0xAA - b ^= B00000011; // B00000011 == 0x3 - -then we will have :: - - b == B10101001; // B10101001 == 0xA9 - -See Also --------- - -- :ref:`Boolean operations <lang-boolean>` (``&&``, ``||``) -- :ref:`Bitwise operators <lang-bitwisemath>` (``&``, ``|``, ``^``, ``~``) - -.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/const.rst b/docs/source/lang/cpp/const.rst deleted file mode 100644 index ad0c580..0000000 --- a/docs/source/lang/cpp/const.rst +++ /dev/null @@ -1,50 +0,0 @@ -.. highlight:: cpp - -.. _lang-const: - -``const`` -========= - -The ``const`` keyword stands for "constant". It is a variable -*qualifier* that modifies the behavior of the variable, making a -variable "*read-only*". This means that the variable can be used just -as any other variable of its type, but its value cannot be -changed. You will get a compiler error if you try to assign a value to -a ``const`` variable. - -Constants defined with the ``const`` keyword obey the same rules of -:ref:`variable scoping <lang-scope>` that govern other -variables. This, and the pitfalls of using :ref:`#define -<lang-define>`, often makes using the ``const`` keyword a superior -method for defining constants than ``#define``. - -Example -------- - - :: - - // this defines a variable called "pi", which cannot be changed: - const float pi = 3.14; - float x; - - // .... - - x = pi * 2; // it's fine to find the value of a const variable - - pi = 7; // illegal - you can't write to (modify) a constant - -**#define** or **const** ------------------------- - -You can use either ``const`` or ``#define`` for creating numeric or -string constants. For :ref:`arrays <lang-array>`\ , you will need -to use ``const``. In general, ``const`` is preferred over ``#define`` -for defining constants. - -See Also --------- - -- :ref:`#define <lang-define>` -- :ref:`volatile <lang-volatile>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/continue.rst b/docs/source/lang/cpp/continue.rst deleted file mode 100644 index 2a694f6..0000000 --- a/docs/source/lang/cpp/continue.rst +++ /dev/null @@ -1,30 +0,0 @@ -.. highlight:: cpp - -.. _lang-continue: - -``continue`` -============ - -The ``continue`` keyword skips the rest of the current iteration of a -:ref:`while <lang-while>`\ , :ref:`for <lang-for>`\ , or -:ref:`do/while <lang-dowhile>` loop. It continues by checking the -conditional expression of the loop, and proceeding with any subsequent -iterations. - -Example -------- - -:: - - - for (x = 0; x < 255; x ++) { - if (x > 40 && x < 120) { // create jump in values - continue; // skips the next two lines and goes to the - // beginning of the loop, with the next value of x - } - - digitalWrite(PWMpin, x); - delay(50); - } - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/curly-braces.rst b/docs/source/lang/cpp/curly-braces.rst deleted file mode 100644 index df2fe2a..0000000 --- a/docs/source/lang/cpp/curly-braces.rst +++ /dev/null @@ -1,106 +0,0 @@ -.. highlight:: cpp - -.. _lang-curly-braces: - -Curly Braces (``{``, ``}``) -=========================== - -.. contents:: Contents - :local: - -Introduction ------------- - -Curly braces (also referred to as just "braces" or as "curly -brackets") are a major part of the C and C++ programming -languages. They are used in several different constructs, outlined -below, and this can sometimes be confusing for beginners. - -An opening curly brace, ``{`` must always be followed by a closing -curly brace ``}``. This is a condition that is often referred to as -the braces being *balanced*. The Maple IDE (integrated development -environment) includes a convenient feature to check the balance of -curly braces. Just select a brace, or even click the insertion point -immediately following a brace, and its companion will be highlighted\ -[#fbug]_\ . - -Beginning programmers, and programmers coming to C++ from languages -without braces, often find using them confusing or daunting. - -Because the use of the curly brace is so varied, it is good -programming practice to type the closing brace immediately after -typing the opening brace when inserting a construct which requires -curly braces. Then insert some blank lines between your braces and -begin inserting statements. Your braces, and your attitude, will never -become unbalanced. - -Unbalanced braces can often lead to cryptic, impenetrable compiler -errors that can sometimes be hard to track down in a large program. -Because of their varied usages, braces are also incredibly important -to the syntax of a program and moving a brace one or two lines will -usually dramatically affect the meaning of a program. - -The main uses of curly braces ------------------------------ - -**Functions**:: - - // a function body needs braces around it - void myFunction(datatype argument) { - // ... function body goes in here ... - } - -**Loops** (see the :ref:`while <lang-while>`\ , :ref:`for -<lang-for>`\ , and :ref:`do/while <lang-dowhile>` loop reference -pages for more information):: - - // you should put braces around the body of a loop: - - while (boolean expression) { - // code inside the loop goes here - } - - for (initialisation; termination condition; incrementing expr) { - // code inside the loop goes here - } - - do { - // code inside the loop goes here - } while (boolean expression); - - -**Conditional statements** (see the :ref:`if statement <lang-if>` -reference page for more information):: - - // you should put braces around the body of an "if", "else if", - // or "else": - - if (boolean expression) { - // code inside the "if" - } - else if (boolean expression) { - // code inside the "else if" - } - else { - // code inside the "else" - } - -**Switch statements** (see the :ref:`switch statement -<lang-switchcase>` reference page for more information):: - - switch (var) { - case 1: - doThing1(); - break; - case 2: - doThing2(); - break; - } - -.. rubric:: Footnotes - -.. [#fbug] At present this feature is slightly buggy as the IDE will - often find (incorrectly) a brace in text that has been commented - out. - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/define.rst b/docs/source/lang/cpp/define.rst deleted file mode 100644 index b22085f..0000000 --- a/docs/source/lang/cpp/define.rst +++ /dev/null @@ -1,54 +0,0 @@ -.. highlight:: cpp - -.. _lang-define: - -``#define`` -=========== - -``#define`` is a useful C and C++ feature that allows the programmer -to give a name to a constant value before the program is compiled. -The compiler will replace references to these constants with the -defined value at compile time. - -This can have some unwanted side effects. In general, the :ref:`const -<lang-const>` keyword is preferred for defining constants. - -Syntax ------- - -The following line would define the name ``MY_CONSTANT`` to have value -``value``:: - - #define MY_CONSTANT value - -Note that the ``#`` is necessary. It is usually good style for the -name to be capitalized, although this is not required. - -There is no semicolon after the #define statement. If you include one, -the compiler will likely throw cryptic errors in unrelated places. -That is, **don't do this**:: - - // DON'T DO THIS! THE SEMICOLON SHOULDN'T BE THERE! - #define NAME value; - -Similarly, including an equal sign after the ``#define`` line will -also generate a cryptic compiler error further down the page. That -is, **don't do this, either**:: - - // DON'T DO THIS, EITHER! THE EQUALS SIGN SHOULDN'T BE THERE! - #define NAME = value - -Example -------- - - :: - - #define MAPLE_LED_PIN 13 - // The compiler will replace any mention of MAPLE_LED_PIN with - // the value 13 at compile time. - -See Also --------- -- :ref:`const <lang-const>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/double.rst b/docs/source/lang/cpp/double.rst deleted file mode 100644 index 59422eb..0000000 --- a/docs/source/lang/cpp/double.rst +++ /dev/null @@ -1,46 +0,0 @@ -.. _lang-double: - -``double`` -========== - -Double precision floating point type. Occupies 8 bytes. On Maple, the -``double`` type has a range of approximately -1.79769×10^308 to -1.79769×10^308; the ``double`` type subject to the same :ref:`overflow -issues <lang-variables-rollover>` as any numeric data type. - -Floating point numbers are not exact, and may yield strange results -when compared. For example ``6.0 / 3.0`` may not equal ``2.0``. You -should instead check that the absolute value of the difference between -the numbers is less than some small number. - -Floating point math is also much slower than integer math in -performing calculations, so should be avoided if, for example, a loop -has to run at top speed for a critical timing function. Programmers -often go to some lengths to convert floating point calculations to -integer math to increase speed. - -For more information, see the `Wikipedia article on floating point -math <http://en.wikipedia.org/wiki/Floating_point>`_\ . - -Floating-point numbers represent numbers with "decimal point", unlike -integral types, which always represent whole numbers. Floating-point -numbers are often used to approximate analog and continuous values -because they have greater resolution than integers. - -The double implementation on the Maple uses twice the number of bytes -as a :ref:`float <lang-float>`, with the corresponding gains in -precision. - -Tip ---- - -Users who borrow code from other sources that includes ``double`` -variables may wish to examine the code to see if the implied range and -precision are different from that actually achieved on the Maple. - -See Also --------- - -- :ref:`float <lang-float>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/doublecast.rst b/docs/source/lang/cpp/doublecast.rst deleted file mode 100644 index d3f32ce..0000000 --- a/docs/source/lang/cpp/doublecast.rst +++ /dev/null @@ -1,27 +0,0 @@ -.. highlight:: cpp - -.. _lang-doublecast: - -``double()`` (cast) -=================== - -Converts a value to the :ref:`double <lang-double>` floating point -data type. Here is an example:: - - int x = 2; - double d = double(x); // d now holds 2.0, a double value - -The value ``x`` can be of any type. However, if ``x`` is not a number -(like an ``int`` or ``long long``), you will get strange results. - -See the :ref:`double <lang-double>` reference for details about the -precision and limitations of ``double`` values on the Maple. - -See Also --------- - -- :ref:`double <lang-double>` -- :ref:`float <lang-float>` -- :ref:`float() <lang-floatcast>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/dowhile.rst b/docs/source/lang/cpp/dowhile.rst deleted file mode 100644 index d229122..0000000 --- a/docs/source/lang/cpp/dowhile.rst +++ /dev/null @@ -1,26 +0,0 @@ -.. highlight:: cpp - -.. _lang-dowhile: - -``do``/``while`` -================ - -A ``do`` loop works in the same manner as a :ref:`while -<lang-while>` loop, with the exception that the condition is tested -at the end of the loop, so the ``do`` loop will *always* run at least -once. - -This is the basic syntax:: - - do { - // statement block - } while (test condition); - -Example:: - - do { - delay(50); // wait for sensors to stabilize - x = readSensors(); // check the sensors - } while (x < 100); - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/enum.rst b/docs/source/lang/cpp/enum.rst deleted file mode 100644 index b6409eb..0000000 --- a/docs/source/lang/cpp/enum.rst +++ /dev/null @@ -1,52 +0,0 @@ -.. highlight:: cpp - -.. _lang-enum: - -``enum`` -======== - -The ``enum`` keyword is used to specify an enumeration type. An -enumeration type is a type whose values are taken from a specified, -fixed list of constant values. - -Example -------- - -Here's an example defining an enumeration type called ``weather``, -which has values ``HOT``, ``COMFY``, and ``COLD``:: - - enum weather {HOT, COMFY, COLD}; - -Once you've defined this type, you can create variables of type -``weather``, in the same way you would with an :ref:`int <lang-int>`:: - - // create a weather variable named theWeather, with value COMFY: - weather theWeather = COMFY; - -Enumeration types are useful within :ref:`switch statements -<lang-switchcase>`. If you know that an argument is of an enumeration -type, you can make ``case`` statements for all of that type's possible -values, so you know you won't miss anything:: - - void describeWeather(weather currentWeather) { - switch(currentWeather) { - case HOT: - SerialUSB.println("it's hot out"); - break; - case COMFY: - SerialUSB.println("it's nice today"); - break; - case COLD: - SerialUSB.println("it's freezing!"); - break; - } - } - -Such a ``switch`` statement would need no :ref:`default -<lang-switchcase-default>`, since we know that ``currentWeather`` must -be either ``HOT``, ``COMFY``, or ``COLD``. - -See Also --------- - -- :ref:`lang-switchcase` diff --git a/docs/source/lang/cpp/float.rst b/docs/source/lang/cpp/float.rst deleted file mode 100644 index 5195fac..0000000 --- a/docs/source/lang/cpp/float.rst +++ /dev/null @@ -1,50 +0,0 @@ -.. highlight:: cpp - -.. _lang-float: - -``float`` -========= - -Single-precision floating point number. Occupies 4 bytes. On Maple, -the ``float`` type has a range of approximately -3.40282×10^38 to -3.40282×10^38; the ``float`` type is subject to the same -:ref:`overflow issues <lang-variables-rollover>` as any numeric data -type. - -``float``\ s have only 6-7 decimal digits of precision. That means the -total number of digits, not the number to the right of the decimal -point. You can get more precision by using a :ref:`double -<lang-double>` (which has a precision of about 16 decimal digits). - -The following example declares a ``float`` value named ``myfloat``:: - - float myfloat; - -This example declares a ``float`` value named ``sensorCalibrate``, -with value 1.117:: - - float sensorCalibrate = 1.117; - -The general syntax for declaring a float named ``var`` with value -``val`` is:: - - float var = val; - -Here is a more extended example involving a :ref:`float cast -<lang-floatcast>`:: - - int x; - int y; - float z; - - x = 1; - y = x / 2; // y now contains 0, ints can't hold fractions - z = float(x) / 2; // z now contains .5 - -See Also --------- - -- :ref:`double <lang-double>` -- :ref:`Variables <lang-variables>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/floatcast.rst b/docs/source/lang/cpp/floatcast.rst deleted file mode 100644 index af92543..0000000 --- a/docs/source/lang/cpp/floatcast.rst +++ /dev/null @@ -1,28 +0,0 @@ -.. highlight:: cpp - -.. _lang-floatcast: - -``float()`` (cast) -================== - -Converts a value to the :ref:`float <lang-float>` data type. Here is -an example (see the :ref:`constants reference <lang-constants-fp>` for -an explanation of the "2.0f"):: - - int x = 2; - float f = float(x); // f now holds 2.0f, a float value - -The value ``x`` can be of any type. However, if ``x`` is not a number -(like an ``int``), you will get strange results. - -See the :ref:`float <lang-float>` reference for details about the -precision and limitations of ``float`` values on the Maple. - -See Also --------- - -- :ref:`float <lang-float>` -- :ref:`double <lang-double>` -- :ref:`double() <lang-doublecast>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/for.rst b/docs/source/lang/cpp/for.rst deleted file mode 100644 index 78ea562..0000000 --- a/docs/source/lang/cpp/for.rst +++ /dev/null @@ -1,142 +0,0 @@ -.. highlight:: cpp - -.. _lang-for: - -``for`` -======= - -A ``for`` loop is used to repeat a block of statements enclosed in -curly braces. ``for`` loops are useful for performing repetitive -operations, and are often used in combination with :ref:`arrays -<lang-array>` to operate on collections of data or multiple -:ref:`pins <gpio>`. A ``for`` loop is composed of two parts: first, a -*header*, which sets up the for loop, and then a *body*, which is made -up of lines of code enclosed in curly braces. - -.. contents:: Contents - :local: - -Syntax ------- - -There are three parts to the ``for`` loop header: an *initialization* -expression, *loop condition* expression, and a *post-loop* -expression. The general syntax looks like this:: - - for (initialization; condition; post-loop) { - // all of these lines inside the curly braces are part - // of the loop body. - statement 1; - statement 2; - ... - } - -(Note that there is no semicolon after the post-loop). The -initialization happens first and exactly once, before the loop begins. -Each time through the loop, the condition is tested. The condition is -a :ref:`boolean <lang-boolean>` expression. If it is true, then the -list of statements inside the curly braces are executed. Next, the -post-loop is executed. The loop then begins again by evaluating the -condition again, entering the loop body if it is true. This proceeds -until the condition becomes false. - -Examples --------- - -Here's an example:: - - // Dim an LED using a PWM pin - int pwmPin = 9; // LED in series with 470 ohm resistor on pin 9 - - void setup() { - pinMode(pwmPin, PWM); - } - - void loop() { - for (int i=0; i <= 65535; i++) { - pwmWrite(pwmPin, i); - delay(1); - } - } - -There is a ``for`` loop In the :ref:`loop() <lang-loop>` function of -the above example. This loop starts by declaring an ``int`` variable -named ``i``, whose value starts out at zero. The loop proceeds by -checking if ``i`` is less than or equal to 65535. Since ``i`` is -zero, this is true, and so the calls to :ref:`pwmWrite() -<lang-pwmwrite>` and :ref:`delay() <lang-delay>` happen next. At this -point, the post-loop expression ``i++`` is evaluated, which -:ref:`increments <lang-increment>` ``i``, so that ``i`` becomes one. -That concludes the first time through the loop. Each "time through -the loop" is referred to as an *iteration*. - -The loop then jumps back to the beginning, checking the condition as -the beginning of its second iteration (initialization is skipped, -since this only happens once, before the first iteration). One is -less than 65535, so the loop statements are executed again. This -proceeds over and over until the iteration when ``i`` finally -reaches 65536. At that point, the condition is no longer true, so the -loop stops executing, and the ``loop()`` function returns. - -Here's another example, using a ``for`` loop to brighten and fade an -LED (see the :ref:`pwmWrite() <lang-pwmwrite>` reference for more -information):: - - int pwmPin = 9; // hook up the LED to pin 9 - void loop() { - int x = 1; - for (int i = 0; i >= 0; i += x) { - analogWrite(pwmPin, i); // controls the brightness of the LED - if (i == 65535) { - x = -1; // switch direction, so i starts decreasing - } - delay(1); - } - } - -Coding Tips ------------ - -The C ``for`` loop is more flexible than ``for`` loops found in some -other computer languages, including BASIC. Any or all of the three -header elements may be left blank, although the semicolons are -required. Also the statements for initialization, condition, and -post-loop can be any valid C statements, and use any C datatypes, -including :ref:`floating point numbers <lang-double>`. These types -of unusual ``for`` loops sometimes provide solutions to less-common -programming problems. - -For example, using a multiplication in the post-loop line will -generate a `geometric progression -<http://en.wikipedia.org/wiki/Geometric_progression>`_:: - - for(int x = 1; x <= 100; x = x * 2) { - SerialUSB.println(x); - } - - -This loop prints out the numbers 1, 2, 4, 8, ..., 64. Check -your understanding of ``for`` loops by answering the following two -questions (answers are in footnote [#fanswers]_\ ): - -1. How many iterations occur before the loop finishes? - -2. Why does it stop at 64? - -See Also --------- - -- :ref:`while <lang-while>` loops -- :ref:`do <lang-dowhile>` loops - -.. rubric:: Footnotes - -.. [#fanswers] - 1. Seven. - - 2. After the seventh iteration, the post-loop causes ``x`` to - equal 128. This is larger than 100, so the loop condition is - false, and the loop stops. - - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/goto.rst b/docs/source/lang/cpp/goto.rst deleted file mode 100644 index 2c0b3b0..0000000 --- a/docs/source/lang/cpp/goto.rst +++ /dev/null @@ -1,129 +0,0 @@ -.. highlight:: cpp - -.. _lang-goto: - -Labels and ``goto`` -=================== - -A *label* gives a name to a line of code within a function. You can -label a line by writing a name for it, then a colon (``:``), before -the line starts. The ``goto`` keyword allows program flow to transfer -to a labeled line from anywhere within the same function. - -.. warning:: The use of ``goto`` is discouraged in C and C++ - programming. It is *never necessary* to use ``goto`` to write a - program. - - Unless you know what you're doing, using ``goto`` tends to - encourage code which is harder to debug and understand than - programs without ``goto`` that do the same thing. That said, - however, it's sometimes useful; :ref:`see below <goto-when-to-use>` - for a concrete example. - -Using Labels and goto ---------------------- - -Labels and ``goto`` are probably best explained through example. -Let's start with an example of how to label lines. The first line -(``int x = analogRead(some_pin);``) in the :ref:`loop <lang-loop>` -function below has label ``readpin``. The third line (``delay(x);``) -has label ``startdelay``. The second line (``SerialUSB.println(x);``) -does not have a label:: - - void loop() { - readpin: - int x = analogRead(some_pin); - SerialUSB.println(x); // for debugging - startdelay: - delay(x); - // ... more code ... - } - -Anything which can be a :ref:`variable <lang-variables>` name can -be a label. - -Let's say that we wanted to print ``x`` only if it was very large, say -at least 2000. We might want to do this just so anybody watching on a -:ref:`serial monitor <ide-serial-monitor>` would know they were in for -a longer wait than usual. We can accomplish this through the use of a -``goto`` statement that skips the printing if ``x`` is less than -2000:: - - void loop() { - readpin: - int x = analogRead(some_pin); - if (x < 2000) { - goto startdelay; - } - SerialUSB.println(x); // for debugging - startdelay: - delay(x); - // ... more code ... - } - -In this modified program, whenever ``x`` is less than 2000, the body -of the :ref:`if <lang-if>` statement in the second line is -executed. The ``goto`` statement inside the ``if`` body skips -straight to the line labeled ``startdelay``, passing over the line -doing the printing. - -A ``goto`` does not have to "move forwards"; it can go "backwards", -too. For example, the following program prints "5" forever (why?):: - - void loop() { - printfive: - SerialUSB.println(5); - goto printfive; - SerialUSB.println(6); - } - -.. _goto-when-to-use: - -When to Use goto ----------------- - -As mentioned above, use of ``goto`` is `generally discouraged -<http://en.wikipedia.org/wiki/Goto#Criticism_and_decline>`_. However, -when used with care, ``goto`` can simplify certain programs. One -important use case for ``goto`` is breaking out of deeply nested -:ref:`for <lang-for>` loops or :ref:`if <lang-if>` logic blocks. -Here's an example:: - - for(int r = 0; r < 255; r++) { - for(int g = 255; g > -1; g--) { - for(int b = 0; b < 255; b++) { - if (analogRead(0) > 250) { - goto bailout; - } - // more statements ... - } - // innermost loop ends here - } - } - bailout: - // more code here - -In the above example, whenever the :ref:`analog reading -<lang-analogread>` on pin 0 was greater than 250, the program would -jump to the line labeled ``bailout``, exiting all three loops at once. - -While there is already a :ref:`break <lang-break>` keyword for -breaking out of a loop, it will only break out of the *innermost* -loop. So, if instead of saying "``goto bailout;``", there was a -"``break;``" instead, the program would only exit from the loop with -header "``for(int b = 0; b < 255; b++)``". The program would continue -at the line which reads "``// innermost loop ends here``", which is -clearly undesirable if you wanted to leave all three loops at once. - -More examples of when ``goto`` is a good choice are given in Donald -Knuth's paper, "Structured Programming with go to Statements"; see -below for a link. - -See Also --------- - -- Dijkstra, Edsger W. `Go To Statement Considered Harmful <http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.92.4846&rep=rep1&type=pdf>`_ (PDF) - -- Knuth, Donald. `Structured Programming with go to Statements <http://pplab.snu.ac.kr/courses/adv_pl05/papers/p261-knuth.pdf>`_ (PDF) - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/if.rst b/docs/source/lang/cpp/if.rst deleted file mode 100644 index f248b05..0000000 --- a/docs/source/lang/cpp/if.rst +++ /dev/null @@ -1,121 +0,0 @@ -.. highlight:: cpp - -.. _lang-if: - -``if``/``else`` -=============== - -An ``if`` statement is used to execute code when certain conditions -are met. The general syntax for an ``if`` statement is:: - - if (condition) { - body - } - -An ``if`` statement first tests whether its *condition* is true (such -as an input being above a certain number). If the condition is true, -the ``if`` statement executes its *body*, which is made up of lines of -code inside :ref:`curly braces <lang-curly-braces>`. If the condition -is false, the body is not executed. Here's a more concrete example:: - - if (someVariable > 50) { - // do something here - } - -The program tests to see if ``someVariable`` is greater than 50. If it -is, the program executes every line in the curly braces (which in the -above example does nothing, since the body is just the :ref:`comment -<lang-comments>` line "``// do something here``"). - -Put another way, if the statement in parentheses is true, the -statements inside the braces are run. If not, the program skips over -the code. - -An ``if`` statement's condition (which is inside the parentheses after -``if``) often uses one or more :ref:`boolean <lang-boolean>` or -:ref:`comparison <lang-comparison>` operators. - -Writing the if Body -------------------- - -The brackets may be omitted after an ``if`` statement's -conditional. If this is done, the next line (which ends in a -semicolon) becomes the only line in the body. The following three -``if`` statements all do the same thing:: - - if (x > 120) digitalWrite(pin, HIGH); - - if (x > 120) - digitalWrite(pin, HIGH); - - if (x > 120) { - digitalWrite(pin, HIGH); - } - -However, the following two examples are different:: - - // example 1: two lines of code in the if body - if (x > 120) { - digitalWrite(pin1, HIGH); - digitalWrite(pin2, HIGH); - } - - // example 2: one line of code in the if body, and - // another line of code after the if statement - if (x > 120) - digitalWrite(pin1, HIGH); // this is in the if body - digitalWrite(pin2, HIGH); // this is NOT in the if body - -In the first example, since the body is enclosed in curly braces, both -lines are included. In the second example, since the curly braces are -missing, only the first line is in the ``if`` body. - -``else`` --------- - -``if``/\ ``else`` allows greater control over the flow of code than -the basic :ref:`if <lang-if>` statement, by allowing multiple tests to -be grouped together. For example, an :ref:`analog input -<lang-analogread>` could be tested, with one action taken if the input -was less than 500, and another action taken if the input was 500 or -greater. The code would look like this:: - - if (pinFiveInput < 500) { - // action A - } else { - // action B - } - -``else`` can precede another ``if`` test, so that multiple, mutually -exclusive tests can be run at the same time. - -Each test will proceed to the next one until a true test is -encountered. When a true test is found, its associated block of code -is run, and the program then skips to the line following the entire -if/else construction. If no test proves to be true, the default -``else`` block is executed, if one is present, and sets the default -behavior. - -Note that an ``else if`` block may be used with or without a -terminating ``else`` block, and vice-versa. An unlimited number of -such ``else if`` branches is allowed. Here is a code example:: - - if (pinFiveInput < 500) { - // do Thing A - } else if (pinFiveInput >= 1000) { - // do Thing B - } else { - // do Thing C - } - -Another way to express branching, mutually exclusive tests, is with a -:ref:`switch/case <lang-switchcase>` statement. - - -See Also --------- - -- :ref:`boolean operators <lang-boolean>` -- :ref:`comparison operators <lang-comparison>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/include.rst b/docs/source/lang/cpp/include.rst deleted file mode 100644 index 163509d..0000000 --- a/docs/source/lang/cpp/include.rst +++ /dev/null @@ -1,70 +0,0 @@ -.. highlight:: cpp - -.. _lang-include: - -``#include`` -============ - -``#include`` is used to include outside libraries in your sketch. -This gives the programmer access to a large group of standard C -libraries (groups of pre-made functions and data types), and also -libraries written especially for Maple. - -Example -------- - -This example (from the `Arduino LiquidCrystal Tutorial -<http://arduino.cc/en/Tutorial/LiquidCrystal>`_) includes a library -that is used to control :ref:`LCD displays -<libraries-liquid-crystal>`:: - - // include the library code: - #include <LiquidCrystal.h> - - // initialize the library with the numbers of the interface pins - LiquidCrystal lcd(12, 11, 5, 4, 3, 2); - - void setup() { - // set up the LCD's number of columns and rows: - lcd.begin(16, 2); - // Print a message to the LCD. - lcd.print("hello, world!"); - } - - void loop() { - // set the cursor to column 0, line 1 - // (note: line 1 is the second row, since counting begins with 0): - lcd.setCursor(0, 1); - // print the number of seconds since reset: - lcd.print(millis()/1000); - } - -Note that a ``#include`` line, like :ref:`#define <lang-define>`, -has **no semicolon**. The compiler will print strange error messages -if you add one. - -C Standard Library ------------------- - -The standard C library that comes with Maple is called `newlib -<http://sourceware.org/newlib/>`_. Its main sources of documentation -are its `main reference <http://sourceware.org/newlib/libc.html>`_ -page and its `math functions -<http://sourceware.org/newlib/libm.html>`_ reference page. Here's an -example that imports the math.h library in order to take the `cube -root <http://en.wikipedia.org/wiki/Cube_root>`_ of a number:: - - #include <math.h> - - void setup() { - // no setup necessary - } - - void loop() { - // "cbrt" stands for "cube root" - double cubeRootOf3 = cbrt(3.0); - // prints a number that is approximately the cube root of 3: - SerialUSB.println(cubeRootOf3); - } - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/increment.rst b/docs/source/lang/cpp/increment.rst deleted file mode 100644 index c423d1a..0000000 --- a/docs/source/lang/cpp/increment.rst +++ /dev/null @@ -1,37 +0,0 @@ -.. highlight:: cpp - -.. _lang-increment: - -Increment and Decrement Operators (``++``, ``--``) -================================================== - -These operators increment (add one to) or decrement (subtract one -from) a variable. If they come before the variable, they return its -new value; otherwise, they return its old value. - -Some quick examples:: - - x++; // adds one to x, and returns the old value of x - ++x; // adds one to x, and returns the new value of x - - x--; // decrement x by one and returns the old value of x - --x; // decrement x by one and returns the new value of x - -A more extended example:: - - x = 2; - y = ++x; // x now contains 3, y contains 3 - y = x--; // x contains 2 again, y still contains 3 - -.. warning:: Be careful! You cannot put a space in between the two - ``+`` or ``-`` signs. This example is broken:: - - // this line won't compile (notice the extra space): - int y = x+ +; - -See Also --------- - -- :ref:`lang-compoundarithmetic` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/int.rst b/docs/source/lang/cpp/int.rst deleted file mode 100644 index fa63946..0000000 --- a/docs/source/lang/cpp/int.rst +++ /dev/null @@ -1,68 +0,0 @@ -.. highlight:: cpp - -.. _lang-int: - -``int`` -======= - -The ``int`` data type represents integers. Integers are your primary -data type for number storage, and store a 4 byte value. This yields a -range of -2,147,483,648 to 2,147,483,647 (minimum value of -2^31 and a -maximum value of (2^31) - 1; that's about negative 2 billion to -positive 2 billion). - -An ``int`` stores a negative number with a technique called `two's -complement math -<http://en.wikipedia.org/wiki/Two%27s_complement#Explanation>`_\ . -The highest bit in an ``int``, sometimes refered to as the "sign" bit, -flags the number as a negative number. (See the linked article on -two's complement for more information). - -The Maple takes care of dealing with negative numbers for you, so that -arithmetic operations work mostly as you'd expect. There can be an -:ref:`unexpected complication <lang-bitshift-signbit-gotcha>` in -dealing with the :ref:`bitshift right operator (>>) -<lang-bitshift>`, however. - -.. _lang-long: - -The ``long`` type is a synonym for ``int``. - -Here is an example of declaring an ``int`` variable named ``pin``, -then giving it value 13:: - - int pin = 13; - -The general syntax for declaring an ``int`` variable named ``var``, -then giving it value ``val``, looks like:: - - int var = val; - -.. _lang-int-overflow: - -Integer Overflow ----------------- - -When ``int`` variables leave the range specified above, they -:ref:`roll over <lang-variables-rollover>` in the other direction. -Here are some examples:: - - int x; - x = -2,147,483,648; - x--; // x now contains 2,147,483,647; rolled over "left to right" - - x = 2,147,483,647; - x++; // x now contains -2,147,483,648; rolled over "right to left" - -See Also --------- - -- :ref:`unsigned int <lang-unsignedint>` -- :ref:`char <lang-char>` -- :ref:`unsigned char <lang-unsignedchar>` -- :ref:`long long <lang-longlong>` -- :ref:`unsigned long long <lang-unsignedlonglong>` -- :ref:`Integer Constants <lang-constants-integers>` -- :ref:`Variables <lang-variables>` - -.. include:: cc-attribution.txt diff --git a/docs/source/lang/cpp/intcast.rst b/docs/source/lang/cpp/intcast.rst deleted file mode 100644 index da838c7..0000000 --- a/docs/source/lang/cpp/intcast.rst +++ /dev/null @@ -1,26 +0,0 @@ -.. highlight:: cpp - -.. _lang-intcast: - -``int()`` (cast) -================ - -Converts a value to the :ref:`int <lang-int>` data type. Here is -an example:: - - double d = 2.5; - int i = int(d); // i holds "2", an int value - -The value inside of the parentheses (``int(...)``) can be of any type. -However, if it is not a numeric type (like ``double``, ``char``, -etc.), you will get strange results. - -See the :ref:`int <lang-int>` reference for details about the -precision and limitations of ``int`` variables on the Maple. - -See Also --------- - -- :ref:`int <lang-int>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/keywords.rst b/docs/source/lang/cpp/keywords.rst deleted file mode 100644 index f21cd0d..0000000 --- a/docs/source/lang/cpp/keywords.rst +++ /dev/null @@ -1,204 +0,0 @@ -.. _lang-keywords: - -Keywords -======== - -This page lists all of the C++ keywords, and either links to a -reference page explaining their use, or provides a brief description. - -List of Keywords ----------------- - -The C++ keywords are: - -``and``, ``and_eq``, ``asm``, ``auto``, ``bitand``, ``bitor``, -``bool``, ``break``, ``case``, ``catch``, ``char``, ``class``, -``compl``, ``const``, ``const_cast``, ``continue``, ``default``, -``delete``, ``do``, ``double``, ``dynamic_cast``, ``else``, ``enum``, -``explicit``, ``export``, ``extern``, ``false``, ``float``, ``for``, -``friend``, ``goto``, ``if``, ``inline``, ``int``, ``long``, -``mutable``, ``namespace``, ``new``, ``not``, ``not_eq``, -``operator``, ``or``, ``or_eq``, ``private``, ``protected``, -``public``, ``register``, ``reinterpret_cast``, ``return``, ``short``, -``signed``, ``sizeof``, ``static``, ``static_cast``, ``struct``, -``switch``, ``template``, ``this``, ``throw``, ``true``, ``try``, -``typedef``, ``typeid``, ``typename``, ``union``, ``unsigned``, -``using``, ``virtual``, ``void``, ``volatile``, ``wchar_t``, -``while``, ``xor``, ``xor_eq`` - -Boolean Operator Synonyms -------------------------- - -- ``and`` is a synonym for :ref:`&& <lang-boolean-and>`. -- ``not`` is a synonym for :ref:`\! <lang-boolean-not>`. -- ``not_eq`` is a synonym for :ref:`\!= <lang-comparison>`. -- ``or`` is a synonym for :ref:`|| <lang-boolean-or>`. - -Bitwise Operator Synonyms -------------------------- - -- ``and_eq`` is a synonym for :ref:`&= <lang-compoundbitwise-and>`. -- ``bitand`` is a synonym for (bitwise) :ref:`& <lang-bitwisemath-and>`. -- ``bitor`` is a synonym for :ref:`\| <lang-bitwisemath-or>`. -- ``compl`` is a synonym for :ref:`~ <lang-bitwisemath-not>`. -- ``or_eq`` is a synonym for :ref:`|= <lang-compoundbitwise-or>`. -- ``xor`` is a synonym for :ref:`^ <lang-bitwisemath-xor>`. -- ``xor_eq`` is a synonym for :ref:`^= <lang-compoundbitwise-xor>`. - -Constants ---------- - -- ``true`` and ``false`` are the :ref:`boolean constants - <lang-booleanvariables>`. - -Control Flow ------------- - -- ``break`` can exit out of a :ref:`switch statement - <lang-switchcase>` or a :ref:`for <lang-for>`, :ref:`do - <lang-dowhile>`, or :ref:`while <lang-while>` loop. - -- ``case`` defines alternatives in a :ref:`switch statement <lang-switchcase>`. - -- ``continue`` will move control flow to the next iteration of the - enclosing :ref:`for <lang-for>`, :ref:`do <lang-dowhile>`, or - :ref:`while <lang-while>` loop. - -- ``default`` defines the default alternative in a :ref:`switch - statement <lang-switchcase>`. - -- ``do`` introduces a :ref:`do <lang-dowhile>` loop. - -- ``else`` is used in :ref:`if statements <lang-if>`. - -- ``for`` introduces a :ref:`for <lang-for>` loop. - -- ``goto`` :ref:`jumps <lang-goto>` to a label. - -- ``if`` introduces an :ref:`if statement <lang-if>`. - -- ``return`` :ref:`transfers flow to a function's caller <lang-return>`. - -- ``switch`` introduces a :ref:`switch statement <lang-switchcase>`. - -- ``while`` introduces a :ref:`while <lang-while>` loop. - -Types ------ - -The following keywords are used for built-in types. - -- :ref:`bool <lang-booleanvariables>` -- :ref:`char <lang-char>` -- :ref:`double <lang-double>` -- :ref:`float <lang-float>` -- :ref:`int <lang-int>` -- :ref:`long <lang-long>` -- :ref:`short <lang-built-in-types-integral>` -- :ref:`void <lang-void>` (not really a type, but used in the absence - of one) - -The following keywords are used to introduce new types. - -- :ref:`enum <lang-enum>` - -Qualifiers ----------- - -- :ref:`static <lang-static>` can be used to declare persistent local - variables; it has other uses not documented here. - -- ``unsigned`` is used to specify an unsigned integral type. - Examples: :ref:`lang-unsignedint`, :ref:`lang-unsignedchar`. - -- :ref:`volatile <lang-volatile>` is useful when declaring variables - that may be modified by external interrupts. - -- :ref:`const <lang-const>` is used to define constants. - -Other ------ - -These keywords are not described in the Maple documentation. For more -information, consult a C++ reference. - -- ``asm`` is used to insert literal assembly language. - -- ``auto`` is used to declare that a variable has automatic storage. - -- ``catch`` is used in exception handling. Note that the default - flags we pass to :ref:`GCC <arm-gcc>` include ``-fno-exceptions``. - -- ``class`` is used to define classes. - -- ``const_cast`` is used in typecasting. - -- ``delete`` is used to free ``new``\ -allocated storage. Note that - dynamic memory allocation is not available by default on the Maple, - so you'll have to bring your own ``new`` and ``delete`` if you want - this. - -- ``dynamic_cast`` is used in typecasting. - -- ``explicit`` is used to declare constructors that can be called only - explicitly. - -- ``export`` declares a template definition accessible to other - compilation units. - -- ``extern`` can mark a declaration as a declaration and not a - definition, and also grant external linkage to a ``const`` or - ``typedef``. - -- ``friend`` is used to declare that certain functions have access to - a class's private variables. - -- ``inline`` is a compiler hint to inline a function. - -- ``mutable`` specifies that a member can be updated, even when a - member of a ``const`` object. - -- ``namespace`` declares a new namespace. - -- ``new`` dynamically allocates space for a value. Note that dynamic - memory allocation is not available by default on the Maple, so - you'll have to bring your own ``new`` and ``delete`` if you want - this. - -- ``operator`` is used to define type-specific operator overrides. - -- ``private`` declares a private class member. - -- ``protected`` declares a protected class member. - -- ``public`` declares a public class member. - -- ``register`` is a compiler hint to store a variable in a register. - -- ``reinterpret_cast`` is used in typecasting. - -- ``signed`` is the opposite of ``unsigned``. - -- ``static_cast`` is used in typecasting. - -- ``struct`` declares a new struct. - -- ``template`` introduces a template class, function, etc. - -- ``this`` is a pointer to the receiver object. - -- ``throw`` is used in exception handling. Note that the default - flags we pass to :ref:`GCC <arm-gcc>` include ``-fno-exceptions``. - -- ``try`` is used in exception handling. Note that the default - flags we pass to :ref:`GCC <arm-gcc>` include ``-fno-exceptions``. - -- ``typedef`` defines a type synonym. - -- ``union`` defines an untagged union. - -- ``using`` is a directive related to namespaces. - -- ``virtual`` declares a method which may be overridden. - -- ``wchar_t`` is the wide character type. diff --git a/docs/source/lang/cpp/longcast.rst b/docs/source/lang/cpp/longcast.rst deleted file mode 100644 index 493ad67..0000000 --- a/docs/source/lang/cpp/longcast.rst +++ /dev/null @@ -1,27 +0,0 @@ -.. highlight:: cpp - -.. _lang-longcast: - -``long()`` (cast) -================= - -Converts a value to the :ref:`long <lang-long>` data type. Here is -an example:: - - double d = 2.5; - long i = long(d); // i holds "2L", an long value - -The value inside of the parentheses (``long(...)``) can be of any type. -However, if it is not a numeric type (like ``double``, ``char``, -etc.), you will get strange results. - -See the :ref:`long <lang-long>` reference for details about the -precision and limitations of ``long`` variables on the Maple. - -See Also --------- - -- :ref:`long <lang-long>` -- :ref:`long long <lang-longlong>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/longlong.rst b/docs/source/lang/cpp/longlong.rst deleted file mode 100644 index d942cb4..0000000 --- a/docs/source/lang/cpp/longlong.rst +++ /dev/null @@ -1,56 +0,0 @@ -.. highlight:: cpp - -.. _lang-longlong: - -``long long`` -============= - -The ``long long`` data type stores extended size integer values. You -can use a ``long long`` when your values are too large to fit into an -:ref:`int <lang-int>`. A ``long long`` occupies 8 bytes of memory. -This yields a range of approximately -9.2×10^18 to 9.2×10^18 (that's -9.2 billion billion, or about 92 million times the number of stars in -the Milky Way galaxy). The exact range of a ``long long`` on the -Maple is from -9,223,372,036,854,775,808 to 9,223,372,036,854,775,807, -or -2^63 to (2^63-1). A ``long long`` it is subject to the same -:ref:`overflow issues <lang-variables-rollover>` as any numeric data -type. - -A synonym for the ``long long`` type is ``int64``. - -Here's an example of declaring a long long (see :ref:`integer -constants <lang-constants-integers-u-l>` for an explanation of the -"LL" at the end of the number):: - - // Speed of light in nanometers per second (approximate). - long long c = 299792458000000000LL; - -The general syntax for declaring an ``long long`` variable named ``var``, -then giving it value ``val``, looks like:: - - long long var = val; - -This is identical to the ``int`` syntax, with ``long long`` (or, at -your option, ``int64``) replacing ``int``. - -Note that ``long long`` values will still :ref:`overflow -<lang-int-overflow>`, just like ``int`` values, but their much larger -range makes this less likely to happen. - -The downside to using a ``long long`` instead of an ``int`` (besides -the extra storage) is that :ref:`arithmetic <lang-arithmetic>` -operations on ``long long``\ s will take slightly longer than on -``int``\ s. - -See Also --------- - -- :ref:`char <lang-char>` -- :ref:`unsigned char <lang-unsignedchar>` -- :ref:`int <lang-int>` -- :ref:`unsigned int <lang-unsignedint>` -- :ref:`unsigned long long <lang-unsignedlonglong>` -- :ref:`Integer Constants <lang-constants-integers>` -- :ref:`Variables <lang-variables>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/modulo.rst b/docs/source/lang/cpp/modulo.rst deleted file mode 100644 index 013d07e..0000000 --- a/docs/source/lang/cpp/modulo.rst +++ /dev/null @@ -1,70 +0,0 @@ -.. highlight:: cpp - -.. _lang-modulo: - -Modulo Operator (``%``) -======================= - -Calculates the `remainder <http://en.wikipedia.org/wiki/Remainder>`_ -when one integer is divided by another. It is useful for keeping a -variable within a particular range (e.g. the size of an array). - -Syntax ------- - -:: - - dividend % divisor - -Parameters ----------- - -**dividend**: the number to be divided - -**divisor**: the number to divide by - -Returns -------- - -The remainder of **dividend**\ /\ **divisor**\ . - -Examples --------- - -:: - - int x; - x = 7 % 5; // x now contains 2 - x = 9 % 5; // x now contains 4 - x = 5 % 5; // x now contains 0 - x = 4 % 5; // x now contains 4 - -:: - - /* update one value in an array each time through a loop */ - - int values[10]; - int i = 0; - - void setup() { - // no setup necessary - } - - void loop() { - values[i] = analogRead(0); - i = (i + 1) % 10; // modulo operator makes sure i stays between 0 and 9 - } - -Tip ---- - -The modulo operator does not work on floats. For that, you can use -the C standard library function `fmod() -<http://sourceware.org/newlib/libm.html#fmod>`_. - -See Also --------- - -- :ref:`Arithmetic <lang-arithmetic>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/pointer.rst b/docs/source/lang/cpp/pointer.rst deleted file mode 100644 index ff4ec32..0000000 --- a/docs/source/lang/cpp/pointer.rst +++ /dev/null @@ -1,31 +0,0 @@ -.. _lang-pointer: - -Pointer Operators (``&``, ``*``) -================================ - -The pointer operators ``&`` (reference) and ``*`` (dereference) are -different from the bitwise math operator :ref:`& -<lang-bitwisemath-and>` and the arithmetic operator :ref:`* -<lang-arithmetic>`. - -Pointers are one of the more complicated subjects for beginners in -learning C, and it is possible to write many useful Arduino sketches -without ever encountering pointers. However, for manipulating certain -data structures, the use of pointers can simplify the code, improve -its efficiency, and generally provide many benefits that would be -difficult to achieve without the use of pointers. - -Introducing pointers is somewhat outside the scope of this -documentation. However, a good `pointer tutorial -<http://www.cplusplus.com/doc/tutorial/pointers/>`_ is available. -Also see the `Wikipedia article on pointers -<http://en.wikipedia.org/wiki/Pointer_%28computing%29>`_, especially -the section on `pointers in C -<http://en.wikipedia.org/wiki/Pointer_%28computing%29#C_pointers>`_. - -See Also --------- - -- http://xkcd.com/138/ - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/return.rst b/docs/source/lang/cpp/return.rst deleted file mode 100644 index d9aecbe..0000000 --- a/docs/source/lang/cpp/return.rst +++ /dev/null @@ -1,60 +0,0 @@ -.. highlight:: cpp - -.. _lang-return: - -``return`` -========== - -Terminates a function and return a value from a function to the -calling function, if the function has non-``void`` return type. - -Syntax: -------- - -:: - - // from within a "void" function: - return; - - // from within a non-"void" function: - return value; - -In the second case, ``value`` should have a type which is the same as -the return type of the function, or be convertible to it (like an -``int`` to a ``double``, etc.; see :ref:`this note -<lang-arithmetic-typeconversion>` for some references). - -Examples: ---------- - -A function to compare a sensor input to a threshold:: - - // converts analog readings between 0 and 400 to 0, and 400 up to 1. - int checkSensor() { - if (analogRead(0) > 400) { - return 1; - else { - return 0; - } - } - -An early ``return`` is also useful when testing a section of code -without having to "comment out" large sections of possibly buggy code, -like so:: - - void loop() { - - // brilliant code idea to test here - - return; - - // the rest of a dysfunctional sketch here - // this code will never be executed - } - -See Also --------- - -- :ref:`comments <lang-comments>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/scope.rst b/docs/source/lang/cpp/scope.rst deleted file mode 100644 index a270428..0000000 --- a/docs/source/lang/cpp/scope.rst +++ /dev/null @@ -1,120 +0,0 @@ -.. highlight:: cpp - -.. _lang-scope: - -Scope -===== - -Variables in the C++ programming language, which Maple uses (all of -your sketches are C++ programs in disguise), have a property called -*scope*. Simply put, a variable's scope is made up of all of the -lines where the variable can be used. - -Scope in C++ is a fairly complex topic, so we won't try to describe it -in full here. Instead, we present a simplified view, describing two -different kinds of scopes, *global* and *local*. For more detailed -information, consult a C++ reference. - -Global and Local Variables --------------------------- - -A global variable is one that can be "seen" by every function in a -program. In the :ref:`Maple IDE <ide>`, any variable declared outside -of a function (like :ref:`setup() <lang-setup>` and :ref:`loop() -<lang-loop>`) is a global variable. - -A local variable can only be "seen" inside of a particular function. -You can declare a variable to be local to a function by declaring it -inside of the :ref:`curly braces <lang-curly-braces>` which enclose -that function. - -When programs start to get larger and more complex, local variables -are a useful way to ensure that a function has exclusive access to its -own variables. This prevents programming errors when one function -mistakenly modifies variables used by another function. - -It is also sometimes useful to declare and initialize a variable -inside a :ref:`for <lang-for>` loop. This creates a variable that -can only be accessed from inside the loop body. - -Example -------- - -Here is an example sketch (which you can copy into the Maple IDE and -run on your Maple) that illustrates the use of global and local -variables, as well as declaring variables inside of a ``for`` loop. -Be sure to open a :ref:`serial monitor <ide-serial-monitor>` after you -:ref:`verify <ide-verify>` and :ref:`upload <ide-upload>` the sketch:: - - int globalVar; // any function will see this variable - - void setup() { - // since "globalVar" is declared outside of any function, - // every function can "see" and use it: - globalVar = 50; - - // the variables "i" and "d" declared inside the "loop" function - // can't be seen here. see what happens when you uncomment the - // following lines, and try to Verify (compile) the sketch: - // - // i = 16; - // SerialUSB.print("i = "); - // SerialUSB.println(i); - // d = 26.5; - // SerialUSB.print("d = "); - // SerialUSB.println(d); - } - - void loop() { - // since "i" and "d" are declared inside of the "loop" function, - // they can only be seen and used from inside of it: - int i; - double d; - - for (int j = 0; j < 5; j++) { - // variable i can be used anywhere inside the "loop" function; - // variable j can only be accessed inside the for-loop brackets: - i = j * j; - SerialUSB.print("i = "); - SerialUSB.println(i); - } - - // globalVar can be accessed from anywhere. note how even - // though we set globalVar = 50 in the "setup" function, we can - // see that value here: - SerialUSB.print("globalVar = "); - SerialUSB.println(globalVar); - - // d can be accessed from anywhere inside the "loop" function: - d = 26.5; - SerialUSB.print("d = "); - SerialUSB.print(d); - SerialUSB.println(" (before separateFunction())"); - - separateFunction(); - - // notice how even though separateFunction() has a variable - // named "d", it didn't touch our (local) variable which has - // the same name: - SerialUSB.print("d = "); - SerialUSB.print(d); - SerialUSB.println(" (after separateFunction())"); - } - - void separateFunction() { - // variable "d" here has the same name as variable "d" inside of - // the "loop" function, but since they're both _local_ - // variables, they don't affect each other: - double d = 30.5; - SerialUSB.print("d = "); - SerialUSB.print(d); - SerialUSB.println(" (inside of separateFunction())"); - } - -See Also --------- - -- `C++ programming Wikibook <http://en.wikibooks.org/wiki/C%2B%2B_Programming/Programming_Languages/C%2B%2B/Code/Statements/Scope>`_. -- Wikipedia article on `scope <http://en.wikipedia.org/wiki/Scope_%28programming%29>`_ - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/semicolon.rst b/docs/source/lang/cpp/semicolon.rst deleted file mode 100644 index 05e6218..0000000 --- a/docs/source/lang/cpp/semicolon.rst +++ /dev/null @@ -1,22 +0,0 @@ -.. highlight:: cpp - -.. _lang-semicolon: - -Semicolon (``;``) -================= - -Used to end a line of code. Example:: - - int a = 13; - -Tip ---- - -Forgetting to end a line in a semicolon will result in a compiler -error. The error text may be obvious, and refer to a missing -semicolon, or it may not. If an impenetrable or seemingly illogical -compiler error comes up, one of the first things to check is a -missing semicolon, in the immediate vicinity, preceding the line at -which the compiler complained. - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/sizeof.rst b/docs/source/lang/cpp/sizeof.rst deleted file mode 100644 index ec2dea6..0000000 --- a/docs/source/lang/cpp/sizeof.rst +++ /dev/null @@ -1,64 +0,0 @@ -.. highlight:: cpp - -.. _lang-sizeof: - -``sizeof()`` -============ - -The ``sizeof`` operator on the Maple returns the number of bytes -needed to store a value of a given type\ [#fcharsize]_. This can be -an ordinary numeric type, like ``int``. It can be something more -complicated, like a ``struct`` or ``union``. If the argument to -``sizeof`` is an array, it returns the total number of bytes occupied -by the array. - -The general syntax looks like this:: - - sizeof(type) - sizeof(var) - -Example -------- - -The ``sizeof`` operator is useful for dealing with arrays (such as -strings) where it is convenient to be able to change the size of the -array without breaking other parts of the program. - -This program prints out a text string one character at a time. Try -changing the text phrase:: - - char myStr[] = "this is a test"; - int i; - - void setup() { - Serial.begin(9600); - } - - void loop() { - for (i = 0; i < sizeof(myStr) - 1; i++) { - Serial.print(i, DEC); - Serial.print(" = "); - Serial.println(myStr[i], BYTE); - } - } - - -Note that ``sizeof`` returns the total number of bytes. So for larger -variable types such as ``int``, the :ref:`for loop <lang-for>` -would look something like this:: - - for (i = 0; i < (sizeof(myInts)/sizeof(int)) - 1; i++) { - // do something with myInts[i] - } - -.. rubric:: Footnotes - -.. [#fcharsize] Technically (and pedantically) speaking, ``sizeof`` - returns a multiple of the number of bits a ``char`` occupies in - memory. However, on the Maple (this goes for most C++ - implementations), a ``char`` occupies 8 bits = 1 byte. All the C++ - standard guarantees, however, is that a ``char`` occupies at - *least* 8 bits. - -.. include:: /arduino-cc-attribution.txt - diff --git a/docs/source/lang/cpp/sqrt.rst b/docs/source/lang/cpp/sqrt.rst deleted file mode 100644 index fbabf82..0000000 --- a/docs/source/lang/cpp/sqrt.rst +++ /dev/null @@ -1,24 +0,0 @@ -.. _lang-sqrt: - -sqrt() -====== - -Calculates the square root of a number. - -Library Documentation ---------------------- - -.. doxygenfunction:: sqrt - -Arduino Compatibility ---------------------- - -The Maple versino of ``sqrt()`` is compatible with Arduino. - -See Also --------- - -- :ref:`pow <lang-pow>` -- :ref:`sq <lang-sq>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/static.rst b/docs/source/lang/cpp/static.rst deleted file mode 100644 index 8c52ba0..0000000 --- a/docs/source/lang/cpp/static.rst +++ /dev/null @@ -1,56 +0,0 @@ -.. highlight:: cpp - -.. _lang-static: - -``static`` -========== - -The ``static`` keyword can be used to create variables that are -visible to only one function. However, unlike local variables that get -created and destroyed every time a function is called, ``static`` -variables persist beyond the function call, preserving their data -between function calls. - -Variables declared as ``static`` will only be created and initialized -the first time a function is called. - -.. note:: This is only one use of the ``static`` keyword in C++. It - has some other important uses that are not documented here; consult - a reliable C++ reference for details. - -Example -------- - -One use case for ``static`` variables is implementing counters that -last longer than the functions which need them, but shouldn't be -shared to other functions. Here's an example:: - - void setup() { - SerialUSB.begin(); - } - - void loop() { - int reading; - if (timeToReadSensors()) { - reading = readSensors(); - } - // do something with reading - } - - int readSensors() { - static int numSensorReadings = 0; - numSensorReadings++; - if (numSensorReadings % 100 == 0) { - SerialUSB.print("just got to another 100 sensor readings"); - } - return analogRead(...); - } - -In this example, the static variable ``numSensorReadings`` is -initialized to zero the first time ``readSensors()`` is called, and -then incremented, so it starts out at one. Subsequent calls to -``readSensors()`` won't reset ``numSensorReadings`` to zero, because -it was declared ``static``. Thus, ``numSensorReadings`` is a count of -the number of times that ``readSensors()`` has been called. - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/string.rst b/docs/source/lang/cpp/string.rst deleted file mode 100644 index 3497484..0000000 --- a/docs/source/lang/cpp/string.rst +++ /dev/null @@ -1,120 +0,0 @@ -.. highlight:: cpp - -.. _lang-string: - -Strings -======= - -Text strings on the Maple can be represented with null-terminated -arrays of type :ref:`char <lang-char>`. - -Examples --------- - -All of the following are valid declarations for strings:: - - char str1[15]; - char str2[6] = {'m', 'a', 'p', 'l', 'e'}; - char str3[6] = {'m', 'a', 'p', 'l', 'e', '\0'}; - char str4[ ] = "maple"; - char str5[6] = "maple"; - char str6[15] = "maple"; - -As you can see, there are several methods available for declaring and -initializing strings: - -- Declare an array of ``char`` without initializing it, as with ``str1``. - -- Declare an array of ``char`` (with one extra ``char``) and the - compiler will add the required null character, as with ``str2``. - -- Explicitly add the null character (``'\0'``), as with ``str3``. - -- Initialize with a string constant in quotation marks (``"..."``); - the compiler will size the array to fit the string constant and a - terminating null character (``str4``). - -- Initialize the array with an explicit size and string constant, - (``str5``). - -- Initialize the array, leaving extra space for a larger string - (``str6``). - -Null Termination ----------------- - -Generally, strings are terminated with a null character (`ASCII -<http://en.wikipedia.org/wiki/ASCII>`_ code 0). This allows functions -(like ``SerialUSB.print()``) to tell where the end of a string is. -Otherwise, they would continue reading subsequent bytes of memory that -aren't actually part of the string. - -This means that your string needs to have space for one more character -than the text you want it to contain. That is why ``str2`` and -``str5`` need to be six characters, even though "maple" is only five --- the last position is automatically filled with a NULL -character. ``str4`` will be automatically sized to six characters, one -for the extra null. In the case of ``str3``, we've explicitly included -the null character (written ``'\0'``) ourselves. - -Note that it's possible to have a string without a final null -character (e.g. if you had specified the length of ``str2`` as five -instead of six). This will break most functions that use strings, so -you shouldn't do it intentionally. If you notice something behaving -strangely (operating on characters not in the string), however, this -could be the problem. - -Single quotes or double quotes? -------------------------------- - -Strings are always defined inside double quotes (``"Abc"``) and -characters are always defined inside single quotes (``'A'``). - -Wrapping long strings ---------------------- - -You can wrap long strings like this:: - - char myString[] = "This is the first line" - " this is the second line" - " etcetera"; - -Arrays of Strings ------------------ - -It is often convenient, when working with large amounts of text, -such as a project with an LCD display, to setup an array of -strings. Because strings themselves are arrays, this is in actually -an example of a two-dimensional array. - -In the code below, the asterisk after the datatype char ``char *`` -indicates that this is an array of "pointers". All array names are -actually pointers, so this is required to make an array of arrays. -Pointers are one of the more esoteric parts of C for beginners to -understand, but it isn't necessary to understand pointers in detail to -use them effectively here:: - - char* myStrings[] = {"This is string 1", "This is string 2", - "This is string 3", "This is string 4", - "This is string 5", "This is string 6"}; - - void setup() { - SerialUSB.begin(); - } - - void loop() { - for (int i = 0; i < 6; i++) { - SerialUSB.println(myStrings[i]); - delay(500); - } - } - - -See Also --------- - -- :ref:`array <lang-array>` -- :ref:`__attribute__ <arm-gcc-attribute-flash>` -- :ref:`Variables <lang-variables>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/switchcase.rst b/docs/source/lang/cpp/switchcase.rst deleted file mode 100644 index e31ccf3..0000000 --- a/docs/source/lang/cpp/switchcase.rst +++ /dev/null @@ -1,118 +0,0 @@ -.. highlight:: cpp - -.. _lang-switchcase: - -``switch``\ /\ ``case`` -======================= - -Like :ref:`if <lang-if>` statements, A ``switch`` statement controls -program flow by allowing you to specify different code that should be -executed under various cases. - -The general syntax looks like this:: - - switch (var) { - case val1: - // statements - break; - case val2: - // statements - break; - ... - default: - // statements - } - -Where ``var`` is a variable whose value to investigate, and the -``val1``, ``val2`` after each ``case`` are constant values that -``var`` might be. - -Description ------------ - -A ``switch`` statement compares the value of a variable to the values -specified in ``case`` statements. When a ``case`` statement is found -whose value matches that of the variable, the code in that case -statement is run. - -Here's a more concrete example:: - - switch (var) { - case 1: - doThing1(); - break; - case 2: - doThing2(); - break; - } - afterTheSwitch(); - -In the above example, if ``var == 1``, then the code beginning on the -line after ``case 1`` gets executed. That is, if ``var`` is one, -``doThing1()`` gets called first, and then the ``break`` statement is -executed. - -The ``break`` keyword exits the ``switch`` statement, and is typically -used at the end of each ``case``. Since there is a ``break`` at the -end of ``case 1``, the ``switch`` statement exits, and the next line -to be run is the one which calls ``afterTheSwitch()``. - -Without a ``break``, the ``switch`` statement will continue executing -the following ``case`` expressions ("falling-through") until a -``break`` (or the end of the switch statement) is reached. Let's -pretend the ``switch`` looked like this instead:: - - switch (var) { - case 1: - doThing1(); - // no break statement anymore - case 2: - doThing2(); - break; - } - afterTheSwitch(); - -Now, if ``var`` is one, ``doThing1()`` gets executed like before. -However, without a ``break``, the code would continue to be executed -line-by-line, so ``doThing2()`` would be called next. At this point, -a ``break`` has been reached, so the program continues by calling -``afterTheSwitch()``. This is usually not what you want, which is why -each ``case`` usually has a ``break`` at the end. - -.. _lang-switchcase-default: - -Writing "``default:``" instead of a ``case`` statement allows you to -specify what to do if none of the ``case`` statements matches. Having -a ``default`` is optional (you can leave it out), but if you have one, -it must appear after all of the ``case`` statements. Let's add a -``default`` to the ``switch`` we've been discussing:: - - switch (var) { - case 1: - doThing1(); - break; - case 2: - doThing2(); - break; - default: - doSomethingElse(); - } - afterTheSwitch(); - -If ``var`` is one, then ``doThing1()`` gets called. If ``var`` is -two, ``doThing2()`` gets called. If ``var`` is anything else, -``doSomethingElse()`` gets called. As stated above, a ``default`` is -optional. If you're missing one and none of the ``case`` statements -match, the ``switch`` does nothing at all, as if it weren't there. - -``switch`` statements are often used with an :ref:`enum <lang-enum>` -value as the variable to compare. In this case, you can write down -all of the values the ``enum`` takes as ``case`` statements, and be -sure you've covered all the possibilities. - -See Also: ---------- - -- :ref:`if/else <lang-if>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/unsignedchar.rst b/docs/source/lang/cpp/unsignedchar.rst deleted file mode 100644 index 45fedeb..0000000 --- a/docs/source/lang/cpp/unsignedchar.rst +++ /dev/null @@ -1,32 +0,0 @@ -.. highlight:: cpp - -.. _lang-unsignedchar: - -``unsigned char`` -================= - -An unsigned version of the :ref:`char <lang-char>` data type. An -``unsigned char`` occupies 1 byte of memory; it stores an integer from -0 to 255. - -Like an :ref:`unsigned int <lang-unsignedint>`, an ``unsigned char`` -won't store negative numbers; it is also subject to the same -:ref:`overflow issues <lang-int-overflow>` as any integral data type. - -Example -------- - - :: - - unsigned char c = 240; - -See Also --------- - -- :ref:`byte <lang-byte>` -- :ref:`int <lang-int>` -- :ref:`array <lang-array>` -- :ref:`SerialUSB.println() <lang-serialusb-println>` -- :ref:`Serial.println() <lang-serial-println>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/unsignedint.rst b/docs/source/lang/cpp/unsignedint.rst deleted file mode 100644 index f8ea473..0000000 --- a/docs/source/lang/cpp/unsignedint.rst +++ /dev/null @@ -1,59 +0,0 @@ -.. highlight:: cpp - -.. _lang-unsignedint: - -``unsigned int`` -================ - -An ``unsigned int`` (unsigned integer) is the same as an :ref:`int -<lang-int>` in that it stores a 4 byte integer value. However, -Instead of storing both negative and positive numbers, an ``unsigned -int`` can only store nonnegative values, yielding a range of 0 to -4,294,967,295 (the positive value is 2^32 - 1). - -The difference between an ``unsigned int`` and a (signed) ``int`` lies -in the way the highest bit, sometimes referred to as the "sign" bit, -is interpreted. In the case of the Maple ``int`` type (which is -signed), if the high bit is a "1", the number is interpreted as a -negative number, using a technique known as `two's complement math -<http://en.wikipedia.org/wiki/Two%27s_complement#Explanation>`_. The -bits in an an ``unsigned int`` are interpreted according to the usual -rules for converting `binary to decimal -<http://en.wikipedia.org/wiki/Binary_numeral_system#Counting_in_binary>`_. - -An ``unsigned int`` is subject to the same :ref:`overflow issues -<lang-int-overflow>` as a regular ``int``; the only difference is -that an ``unsigned int`` will "underflow" at 0, and "overflow" at -4,294,967,295. Here is some example code which illustrates this:: - - unsigned int x; - x = 0; - x--; // x now contains 4,294,967,295; rolled over "left to right" - x++; // x now contains 0; rolled over "right to left" - -.. _lang-unsignedlong: - -The ``unsigned long`` type is a synonym for ``unsigned int``. - -Here is an example of declaring an ``unsigned int`` variable named -``pin``, then giving it value 13:: - - unsigned int pin = 13; - -The general syntax for declaring an ``unsigned int`` variable named -``var``, then giving it value ``val``, looks like:: - - unsigned int var = val; - -See Also --------- - -- :ref:`int <lang-int>` -- :ref:`char <lang-char>` -- :ref:`unsigned char <lang-unsignedchar>` -- :ref:`long long <lang-longlong>` -- :ref:`unsigned long long <lang-unsignedlonglong>` -- :ref:`Integer Constants <lang-constants-integers>` -- :ref:`Variables <lang-variables>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/unsignedlonglong.rst b/docs/source/lang/cpp/unsignedlonglong.rst deleted file mode 100644 index a1143f0..0000000 --- a/docs/source/lang/cpp/unsignedlonglong.rst +++ /dev/null @@ -1,43 +0,0 @@ -.. highlight:: cpp - -.. _lang-unsignedlonglong: - -``unsigned long long`` -====================== - -An unsigned version of the :ref:`long long <lang-longlong>` data type. -An ``unsigned long long`` occupies 8 bytes of memory; it stores an -integer from 0 to 2^64-1, which is approximately 1.8×10^19 (18 -quintillion, or 18 billion billion). - -A synonym for the ``unsigned long long`` type is ``uint64``. - -Like an :ref:`unsigned int <lang-unsignedint>`, an ``unsigned long -long`` won't store negative numbers; it is also subject to the same -:ref:`overflow issues <lang-int-overflow>` as any integral data type. - -Here is an example of declaring an ``unsigned long long`` variable -named ``c``, then giving it value 299,792,458,000,000,000 (see -:ref:`integer constants <lang-constants-integers-u-l>` for an -explanation of the "ULL" at the end of the number):: - - // Speed of light in nanometers per second (approximate). - unsigned long long c = 299792458000000000ULL; - -The general syntax for declaring an ``unsigned long long`` variable named -``var``, then giving it value ``val``, looks like:: - - unsigned long long var = val; - -See Also --------- - -- :ref:`long long <lang-longlong>` -- :ref:`int <lang-int>` -- :ref:`unsigned <lang-unsignedint>` -- :ref:`char <lang-char>` -- :ref:`unsigned char <lang-unsignedchar>` -- :ref:`Integer Constants <lang-constants-integers>` -- :ref:`Variables <lang-variables>` - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/variables.rst b/docs/source/lang/cpp/variables.rst deleted file mode 100644 index 9ffdd1d..0000000 --- a/docs/source/lang/cpp/variables.rst +++ /dev/null @@ -1,169 +0,0 @@ -.. highlight:: cpp - -.. _lang-variables: - -Variables -========= - -A variable is a way of naming and storing a value for later use by -the program, such as data from a sensor or an intermediate value -used in a calculation. - -.. contents:: Contents - :local: - -.. _lang-variables-declaring: - -Declaring Variables -------------------- - -Before they are used, all variables have to be *declared*. Declaring a -variable means defining its type, giving it a name, and (optionally) -giving it an initial value (this is often referred to as -*initializing* the variable). Variables do not have to be initialized -(given a value) when they are declared, but it is good style to give -them an initial value whenever possible. - -Here is an example of declaring a variable named ``inputVariable1`` -with type :ref:`int <lang-int>` (the ``int`` type is used to store -integers, like -2, -1, 0, 1, etc.):: - - int inputVariable1; - -In the above declaration, we did not give the variable an initial -value. Here is another example, where we declare an ``int`` variable -named ``inputVariable2``, with an initial value of ``0``:: - - int inputVariable2 = 0; - -The Maple environment comes ready to use with many useful types of -variables. See the :ref:`built-in types <lang-built-in-types>` page -for more information. - -Here are a few examples of declaring variables of different types:: - - int lightSensVal; - char currentLetter; - unsigned long long speedOfLight = 186000ULL; - char errorMessage = {"choose another option"}; // see string - -Naming Variables ----------------- - -The rules for naming a variable are simple. Names for variables can -contain letters, numbers, and underscores (the underscore is the -:kbd:`_` character), and cannot begin with a number. So -``temperature_reading``, ``tempReading``, ``tempReading1``, and -``tempReading2`` are all valid variable names, but ``4_temp_readings`` -is not, because it begins with a number. - -You cannot choose a name for a variable that is one of the C++ -:ref:`keywords <lang-keywords>`. - -Variable names are case-sensitive, so "tempreading" and "tempReading" -are different variables. However, it is very bad style to write code -that chooses variables which are the same up to case. - -You should give your variables descriptive names, so as to make your -code more readable. Variable names like ``tiltSensor`` or -``pushButton`` help you (and anyone else reading your code) understand -what the variable represents. Variable names like ``var`` or -``value``, on the other hand, do little to make your code readable. - -.. _lang-variables-scope: - -Variable Scope --------------- - -An important choice that programmers face is where (in the program -text) to declare variables. The specific place that variables are -declared influences how various functions in a program will "see" the -variable. This is called variable *scope*. See the :ref:`scope -reference <lang-scope>` for more information. - -.. _lang-variables-initializing: - -Initializing Variables ----------------------- - -Variables may be *initialized* (assigned a starting value) when they -are declared or not. It is always good programming practice however to -double check that a variable has valid data in it before it is used. -Using a variable before you give it a value is a common source of -bugs. - -.. _lang-variables-rollover: - -Variable Rollover ------------------ - -Every (numeric) type has a valid *range*. The range of a type is the -smallest and largest value that a variable of that type can store. -For example, the :ref:`int <lang-int>` type has a range of --2,147,483,648 to 2,147,483,647 [#frange]_. - -When variables are made to exceed their range's maximum value, they -"roll over" back to their minimum value. Note that this happens in -both directions. It's like in the game *Pac-Man* -- when Pac-Man goes -past the right edge of the screen, he reappears on the left, and when -he goes past the left side of the screen, he reappears on the right:: - - int x; - x = -2,147,483,648; - x = x - 1; // x now contains -2,147,483,647; rolled over "left to right" - - x = 2,147,483,647; - x = x + 1; // x now contains -2,147,483,648; rolled over "right to left" - -Each numeric type's reference page includes its range. See the -:ref:`built-in types <lang-built-in-types>` reference for links to each -type's reference page. - -Using Variables ---------------- - -Once variables have been declared, they are given values using the -:ref:`assignment operator <lang-assignment>`, which is a single equals -sign, ``=``. The assignment operator tells the program to store the -value on the right side of the equals sign into the variable on the -left side:: - - inputVariable1 = 7; // sets variable named inputVariable1 to 7 - inputVariable2 = analogRead(2); // sets variable named inputVariable2 to - // the (digitized) input voltage read from - // analog pin #2 - -Once a variable has been set (assigned a value), you can test its -value to see if it meets certain conditions, or you can use its value -directly. For instance, the following code tests whether the -inputVariable2 is less than 100, then sets a delay based on -inputVariable2 (which, at that point, is at least 100):: - - if (inputVariable2 < 100) { - inputVariable2 = 100; - } - - delay(inputVariable2); - -See Also --------- - -- :ref:`lang-scope` -- :ref:`lang-built-in-types` - -.. rubric:: Footnotes - -.. [#frange] This range might seem a little weird at first. The - reasons for this range of values have to do with the fact that an - ``int`` occupies 32 bits of memory, and the facts :: - - 2^31 = -2,147,483,648 - 2^31 - 1 = 2,147,483,647 - - - Why 2^31 instead of 2^32? Well, that has to do with `how ints are - (usually) stored - <http://en.wikipedia.org/wiki/Two%27s_complement>`_ on computers. - -.. include:: /arduino-cc-attribution.txt - diff --git a/docs/source/lang/cpp/void.rst b/docs/source/lang/cpp/void.rst deleted file mode 100644 index 7af0acd..0000000 --- a/docs/source/lang/cpp/void.rst +++ /dev/null @@ -1,31 +0,0 @@ -.. highlight:: cpp - -.. _lang-void: - -``void`` -======== - -.. cpp:type:: void - - The ``void`` keyword is used in function declarations. It indicates - that the function is expected to return no information to the - function from which it was called, or that it expects no arguments - from its caller. - -Example -------- - -:: - - // actions are performed in the functions "setup" and "loop" - // but no information is reported to the larger program - - void setup() { - // ... - } - - void loop() { - // ... - } - -.. include:: /arduino-cc-attribution.txt diff --git a/docs/source/lang/cpp/while.rst b/docs/source/lang/cpp/while.rst deleted file mode 100644 index e66e0aa..0000000 --- a/docs/source/lang/cpp/while.rst +++ /dev/null @@ -1,38 +0,0 @@ -.. highlight:: cpp - -.. _lang-while: - -``while`` -========= - -Syntax ------- - -:: - - while (expression) { - // block of code - } - -Description ------------ - -``while`` loops will repeat the statements inside their associated -block of code until the expression inside the parentheses becomes -:ref:`false <lang-constants-false>`. Something must change the tested -expressions' value, or the ``while`` loop will never exit. This could -be in your code, such as an incremented variable, or an external -condition, such as testing a sensor. - -Example -------- - -:: - - var = 0; - while(var < 200) { - // do something repetitive 200 times - var++; - } - -.. include:: /arduino-cc-attribution.txt |