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.. 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
|
