C++ cmath abs()

The abs function is identical to fabs() in C++.

The function is defined in <cmath> header file.

[Mathematics] |x| = abs(x) [C++ Programming]

abs() prototype [As of C++ 11 standard]

double abs(double x);
float abs(float x);
long double abs(long double x);
double abs(T x); // For integral type

The abs() function takes a single argument and returns a value of type double, float or long double type.

abs() Parameters

The abs() function takes a single argument, x whose absolute value is returned.

abs() Return value

The abs() function returns the absolute value of x i.e. |x|.

Example 1: How abs() function works in C++?

#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    double x = -87.91, result;
    
    result = abs(x);
    cout << "abs(" << x << ") = |" << x << "| = " << result << endl;

    return 0;
}

When you run the program, the output will be:

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

Example 2: abs() function for integral types

#include <iostream>
#include <cmath>

using namespace std;

int main()
{
    long int x = -101;
    double result;

    result = abs(x);
    cout << "abs(" << x << ") = |" << x << "| = " << result << endl;

    return 0;
}

When you run the program, the output will be:

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