.. 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 ``ledPin``, then giving it value 13:: unsigned int ledPin = 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