C library function fabs() usage and example

C Standard Library <math.h>

The fabs(x) function returns the absolute value of the parameter x.

fabs() function prototype

double fabs(double x);

The fabs() function takes a parameter (in double form) and returns the absolute value of the number (in double form).

[Math] |x| = fabs(x) [C language]

To find the absolute value of an integer or floating-point number, you can explicitly convert the number to double.

　int x = 0;
　double result;
　result = fabs(double(x));

fabs() function inmath.hDefined in header file

Example: C fabs() function

#include <stdio.h>
#include <math.h>
int main()
{
　　　　double x, result;
　　　　x ==　-1.5;
　　　　result = fabs(x);
　　　　printf("|%.2lf| = 0.2lf\n", x, result);
　　　　x ==　11.3;
　　　　result = fabs(x);
　　　　printf("|%.2lf| = 0.2lf\n", x, result);
　　　　x = 0;
　　　　result = fabs(x);
　　　　printf("|%.2lf| = 0.2lf\n", x, result);
　　　　return 0;
}

Output Result

|-1.50| =　　1.50
|11.30| =　　11.30
|0.00| = 0.00

C Standard Library <math.h>