constrain()

Description

Constrains a number to be within a range.

Syntax

constrain(x, a, b)

Parameter Values

  • x: the number to constrain Allowed data types: all data types.
  • a: the lower end of the range. Allowed data types: all data types.
  • b: the upper end of the range. Allowed data types: all data types.

Return Values

  • x: if x is between a and b.
  • a: if x is less than a.
  • b: if x is greater than b.

Example Code

The code limits the sensor values to between 10 to 150.

sensVal = constrain(sensVal, 10, 150); // limits range of sensor values to between 10 and 150

※ NOTES AND WARNINGS:

Because of the way the constrain() function is implemented, avoid using other functions inside the brackets, it may lead to incorrect results.

This code will yield incorrect results:

int constrainedInput = constrain(Serial.parseInt(), minimumValue, maximumValue); // avoid this

Use this instead:

int input = Serial.parseInt(); // keep other operations outside the constrain function int constrainedInput = constrain(input, minimumValue, maximumValue);

See Also

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