Booleans

A boolean holds one of two values, true or 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

• Boolean constants
• Boolean operators
• Variables

License and Attribution

Portions of this page were adapted from the Arduino Reference Documentation, which is released under a Creative Commons Attribution-ShareAlike 3.0 License.