fabs
floating-point absolute value function
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Interface
#include <math.h>
double fabs ( double x )
long double fabsl ( long double x )
float fabsf ( float x )Description
The fabs functions compute the absolute value of a floating-point number x, which is given by:
$$\mathrm{fabs}(x) :=\begin{cases}
x, & x \geq 0 \\
-x, & x < 0
\end{cases}$$
(1)
Example 1
Workings
#include <stdio.h>
#include <math.h>
int main(void)
{
float number = -1234.0;
printf("number: %.2f absolute value: %.2f\n", number, fabs(number));
return 0;
}Solution
Output:
number: -1234.00 absolute value: 1234.00Special Values
fabs ( ±0 ) returns 0.
fabs ( ±∞ ) returns +∞.
See Also
Standards
The fabs functions conform to ISO/IEC 9899:1999(E).