C++ cmath abs()

#include <iostream>
#include <cmath>
using namespace std;

int main() {

  // get absolute value of -5.5
  cout << abs(-5.5);

  return 0;
}

// Output: 5.5

Syntax of abs()

The syntax of the abs() function is:

abs(double num);

abs() Parameters

The abs() function takes the following parameter:

• num - a floating point number whose absolute value is returned. It can be of the following types:
  • double
  • float
  • long double

abs() Return Value

The abs() function returns:

• the absolute value of num i.e. |num|

abs() Prototypes

The prototypes of abs() as defined in the cmath header file are:

double abs(double num);

float abs(float num);

long double abs(long double num);

// for integral types
double abs(T num);

Note: The cmath abs() function is identical to the fabs() function.

Example 1: C++ abs()

#include <iostream>
#include <cmath>
using namespace std;

int main() {
  double num = -87.91, result;
    
  result = abs(num);

  cout << "abs(" << num << ") = |" << num << "| = " << result;

  return 0;
}

Output

abs(-87.91) = |-87.91| = 87.91

Example 2: C++ abs() for Integral Types

#include <iostream>
#include <cmath>

using namespace std;

int main() {
  int num = -101;
  double result;

  result = abs(num);

  cout << "abs(" << num << ") = |" << num << "| = " << result;

  return 0;
}

Output

abs(-101) = |-101| = 101