fmod() — Calculate Floating-Point Remainder

Format

#include <math.h>
double fmod(double x, double y);

Language Level

ANSI

Threadsafe

Yes

Description

The fmod() function calculates the floating-point remainder of x/y. The absolute value of the result is always less than the absolute value of y. The result will have the same sign as x.

Return Value

The fmod() function returns the floating-point remainder of x/y. If y is zero or if x/y causes an overflow, fmod() returns 0. The value of errno can be set to EDOM.

Example

This example computes z as the remainder of x/y; here, x/y is -3 with a remainder of -1. 
#include <math.h>
#include <stdio.h>
 
int main(void)
{
   double x, y, z;
 
   x = -10.0;
   y = 3.0;
   z = fmod(x,y);      /* z = -1.0 */
 
   printf("fmod( %lf, %lf) = %lf\n", x, y, z);
}
 
/*******************  Output should be similar to:  ***************
 
fmod( -10.000000, 3.000000) = -1.000000
*/

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