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author | Marti Bolivar <mbolivar@mit.edu> | 2010-11-28 11:23:33 -0500 |
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committer | Marti Bolivar <mbolivar@mit.edu> | 2010-11-28 11:23:33 -0500 |
commit | d9cbd78e29d42e70bb46641dd43ee0772c8c975f (patch) | |
tree | 80a67cba4468dbcd89b3cd23ad56695b1f146c66 /source/arduino/const.rst | |
parent | 546b34076d230b617ba86defb6b90cd934b01878 (diff) | |
download | librambutan-d9cbd78e29d42e70bb46641dd43ee0772c8c975f.tar.gz librambutan-d9cbd78e29d42e70bb46641dd43ee0772c8c975f.zip |
reorganized all the arduino/ docs into a lang/ subdirectory since
they're properly CC attributed now.
Diffstat (limited to 'source/arduino/const.rst')
-rw-r--r-- | source/arduino/const.rst | 52 |
1 files changed, 0 insertions, 52 deletions
diff --git a/source/arduino/const.rst b/source/arduino/const.rst deleted file mode 100644 index b008144..0000000 --- a/source/arduino/const.rst +++ /dev/null @@ -1,52 +0,0 @@ -.. highlight:: cpp - -.. _arduino-const: - -const Keyword -============= - -The ``const`` keyword stands for "constant". It is a variable -*qualifier* that modifies the behavior of the variable, making a -variable "*read-only*". This means that the variable can be used just -as any other variable of its type, but its value cannot be -changed. You will get a compiler error if you try to assign a value to -a ``const`` variable. - -Constants defined with the ``const`` keyword obey the same rules of -:ref:`variable scoping <arduino-scope>` that govern other -variables. This, and the pitfalls of using :ref:`#define -<arduino-define>`, often makes using the ``const`` keyword a superior -method for defining constants than ``#define``. - -Example -------- - -:: - - // this defines a variable called "pi", which cannot be changed: - const float pi = 3.14; - float x; - - // .... - - x = pi * 2; // it's fine to find the value of a const variable - - pi = 7; // illegal - you can't write to (modify) a constant - - -**#define** or **const** ------------------------- - -You can use either ``const`` or ``#define`` for creating numeric or -string constants. For :ref:`arrays <arduino-array>`\ , you will need -to use ``const``. In general, ``const`` is preferred over ``#define`` -for defining constants. - -See Also --------- - -- :ref:`#define <arduino-define>` -- :ref:`volatile <arduino-volatile>` - - -.. include:: cc-attribution.txt |