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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/unsignedint.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/unsignedint.rst')
-rw-r--r-- | docs/source/arduino/unsignedint.rst | 77 |
1 files changed, 77 insertions, 0 deletions
diff --git a/docs/source/arduino/unsignedint.rst b/docs/source/arduino/unsignedint.rst new file mode 100644 index 0000000..10835fe --- /dev/null +++ b/docs/source/arduino/unsignedint.rst @@ -0,0 +1,77 @@ +.. _arduino-unsignedint: + +unsigned int +============ + +Description +----------- + +Unsigned ints (unsigned integers) are the same as ints in that they +store a 2 byte value. Instead of storing negative numbers however +they only store positive values, yielding a useful range of 0 to +65,535 (2^16) - 1). + + + +The difference between unsigned ints and (signed) ints, lies in the +way the highest bit, sometimes refered to as the "sign" bit, is +interpreted. In the Arduino int type (which is signed), if the high +bit is a "1", the number is interpreted as a negative number, and +the other 15 bits are interpreted with +`2's complement math. <http://en.wikipedia.org/wiki/2's_complement>`_ + + + +Example +------- + +:: + + unsigned int ledPin = 13; + + + +Syntax +------ + +:: + + unsigned int var = val; + + + + +- var - your unsigned int variable name +- val - the value you assign to that variable + + + +Coding Tip +---------- + +When variables are made to exceed their maximum capacity they "roll +over" back to their minimum capacitiy, note that this happens in +both directions + + + +:: + + unsigned int x + x = 0; + x = x - 1; // x now contains 65535 - rolls over in neg direction + x = x + 1; // x now contains 0 - rolls over + + + +See Also +-------- + + +- `byte <http://arduino.cc/en/Reference/Byte>`_ +- `int <http://arduino.cc/en/Reference/Int>`_ +- `long <http://arduino.cc/en/Reference/Long>`_ +- `unsigned long <http://arduino.cc/en/Reference/UnsignedLong>`_ +- `Variable Declaration <http://arduino.cc/en/Reference/VariableDeclaration>`_ + + |