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.. highlight:: cpp
.. _arduino-booleanvariables:
Booleans
========
A **boolean** holds one of two values, :ref:`true
<arduino-constants-true>` or :ref:`false <arduino-constants-false>`.
On a Maple, each boolean variable occupies one byte of memory, and 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 <arduino-constants-bool>`
- :ref:`Boolean operators <arduino-boolean>`
- :ref:`Variables <arduino-variables>`
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