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author | Marti Bolivar <mbolivar@mit.edu> | 2010-10-20 06:46:52 -0400 |
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committer | Marti Bolivar <mbolivar@mit.edu> | 2010-10-20 06:46:52 -0400 |
commit | 22ff1db8a76c7047b61a424ae1fa5f43697fcb34 (patch) | |
tree | bf722c8a5a6bd40e0b33fc4a425e0e5b8b9f4216 /docs/source/arduino/boolean.rst | |
parent | bac6548fe90b0721e191d68df2677beb4b15f60a (diff) | |
download | librambutan-22ff1db8a76c7047b61a424ae1fa5f43697fcb34.tar.gz librambutan-22ff1db8a76c7047b61a424ae1fa5f43697fcb34.zip |
initial check-in of arduino docs in RST format (converted using wget+pandoc)
Diffstat (limited to 'docs/source/arduino/boolean.rst')
-rw-r--r-- | docs/source/arduino/boolean.rst | 94 |
1 files changed, 94 insertions, 0 deletions
diff --git a/docs/source/arduino/boolean.rst b/docs/source/arduino/boolean.rst new file mode 100644 index 0000000..f109bdb --- /dev/null +++ b/docs/source/arduino/boolean.rst @@ -0,0 +1,94 @@ +.. _arduino-boolean: + +Boolean Operators +================= + +These can be used inside the condition of an +`if <http://arduino.cc/en/Reference/If>`_ statement. + + + +&& (logical and) +~~~~~~~~~~~~~~~~ + +True only if both operands are true, e.g. + +:: + + if (digitalRead(2) == HIGH && digitalRead(3) == HIGH) { // read two switches + // ... + } + +is true only if both inputs are high. + + + +\|\| (logical or) +~~~~~~~~~~~~~~~~~ + +True if either operand is true, e.g. + +:: + + if (x > 0 || y > 0) { + // ... + } + +is true if either x or y is greater than 0. + + + +! (not) +~~~~~~~ + +True if the operand is false, e.g. + +:: + + if (!x) { + // ... + } + +is true if x is false (i.e. if x equals 0). + + + +Warning +------- + +Make sure you don't mistake the boolean AND operator, && (double +ampersand) for the bitwise AND operator & (single ampersand). They +are entirely different beasts. + + + +Similarly, do not confuse the boolean \|\| (double pipe) operator +with the bitwise OR operator \| (single pipe). + + + +The bitwise not ~ (tilde) looks much different than the boolean not +! (exclamation point or "bang" as the programmers say) but you +still have to be sure which one you want where. + + + +Examples +-------- + +:: + + if (a >= 10 && a <= 20){} // true if a is between 10 and 20 + + + +See also +-------- + + +- `& <http://arduino.cc/en/Reference/BitwiseAnd>`_ (bitwise AND) +- `\| <http://arduino.cc/en/Reference/BitwiseAnd>`_ (bitwise OR) +- `~ <http://arduino.cc/en/Reference/BitwiseXorNot>`_ (bitwise NOT +- `if <http://arduino.cc/en/Reference/If>`_ + + |