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author | Hanna Mendes Levitin <hanna@anomaly-3.local> | 2010-12-01 03:37:07 -0600 |
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committer | Hanna Mendes Levitin <hanna@anomaly-3.local> | 2010-12-01 03:37:07 -0600 |
commit | 5a7dd1bea32458a4afc038984a903959134b82d3 (patch) | |
tree | 4171e71c34841212585f855a3fbdf8aaf3b9bb4e /source/lang/cpp/booleanvariables.rst | |
parent | 8e42d34c8d3c81c037a3acaca553ea8c5e4f25aa (diff) | |
download | librambutan-5a7dd1bea32458a4afc038984a903959134b82d3.tar.gz librambutan-5a7dd1bea32458a4afc038984a903959134b82d3.zip |
docs, now with style
Diffstat (limited to 'source/lang/cpp/booleanvariables.rst')
-rw-r--r-- | source/lang/cpp/booleanvariables.rst | 54 |
1 files changed, 54 insertions, 0 deletions
diff --git a/source/lang/cpp/booleanvariables.rst b/source/lang/cpp/booleanvariables.rst new file mode 100644 index 0000000..6051b8c --- /dev/null +++ b/source/lang/cpp/booleanvariables.rst @@ -0,0 +1,54 @@ +.. highlight:: cpp + +.. _lang-booleanvariables: + +Booleans +======== + +A **boolean** holds one of two values, :ref:`true +<lang-constants-true>` or :ref:`false <lang-constants-false>`. On a +Maple, each boolean variable has type ``bool``. + +.. warning:: + + On an Arduino, the type ``boolean`` is also provided. While the + Maple also has this type for compatibility, **its use is strongly + discouraged**. The ``bool`` type is a standard part of C++, while + ``boolean`` is a non-standard extension that serves no purpose. + +Example +------- + +:: + + int ledPin = 13; // LED on pin 13 + int switchPin = 12; // momentary switch on 12, other side connected to ground + + // running is a boolean variable: + bool running = false; + + void setup() { + pinMode(ledPin, OUTPUT); + pinMode(switchPin, INPUT); + digitalWrite(switchPin, HIGH); // turn on pullup resistor + } + + void loop() { + if (digitalRead(switchPin) == LOW) { + // switch is pressed - pullup keeps pin high normally + delay(100); // delay to debounce switch + running = !running; // toggle running variable + digitalWrite(ledPin, running) // indicate via LED + } + } + +See also +-------- + + +- :ref:`Boolean constants <lang-constants-bool>` +- :ref:`Boolean operators <lang-boolean>` +- :ref:`Variables <lang-variables>` + + +.. include:: cc-attribution.txt |