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authorHanna Mendes Levitin <hanna@anomaly-3.local>2010-12-01 03:37:07 -0600
committerHanna Mendes Levitin <hanna@anomaly-3.local>2010-12-01 03:37:07 -0600
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+.. 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