This page is also available in 2 other languages

abs()

[Math]

Description

Calculates the absolute value of a number.

Syntax

abs(x)

Parameters

x: the number

Returns

x: if x is greater than or equal to 0.
-x: if x is less than 0.

Example Code

Prints the absolute value of variable x to the Serial Monitor.

void setup() {
  Serial.begin(9600);
  while (!Serial) {
    ;  // wait for serial port to connect. Needed for native USB port only
  }
  int x = 42;
  Serial.print("The absolute value of ");
  Serial.print(x);
  Serial.print(" is ");
  Serial.println(abs(x));
  x = -42;
  Serial.print("The absolute value of ");
  Serial.print(x);
  Serial.print(" is ");
  Serial.println(abs(x));
}

void loop() {
}

Notes and Warnings

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

abs(a++); // avoid this - yields incorrect results

// use this instead:
abs(a);
a++;  // keep other math outside the function

See also