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diff --git a/docs/source/lang/cpp/int.rst b/docs/source/lang/cpp/int.rst new file mode 100644 index 0000000..ca75f75 --- /dev/null +++ b/docs/source/lang/cpp/int.rst @@ -0,0 +1,64 @@ +.. 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. + +Here is an example of declaring an ``int`` variable named ``ledPin``, +then giving it value 13:: + + int ledPin = 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 <lang-long>` +- :ref:`unsigned long <lang-unsignedlong>` +- :ref:`Integer Constants <lang-constants-integers>` +- :ref:`Variables <lang-variables>` + +.. include:: cc-attribution.txt |