Calculates the floating-point remainder.

double fmod(   
   double x,  
   double y   
);  
float fmod(  
   float x,  
   float y   
);  // C++ only  
long double fmod(  
   long double x,  
   long double y  
);  // C++ only  
float fmodf(   
   float x,  
   float y   
);  

x, y
Floating-point values.

fmod returns the floating-point remainder of x / y. If the value of y is 0.0, fmod returns a quiet NaN. For information about representation of a quiet NaN by the printf family, see printf.

The fmod function calculates the floating-point remainder f of x / y such that x = i * y + f, where i is an integer, f has the same sign as x, and the absolute value of f is less than the absolute value of y.

C++ allows overloading, so you can call overloads of fmod. In a C program, fmod always takes two doubles and returns a double.

For additional compatibility information, see Compatibility in the Introduction.

// crt_fmod.c  
// This program displays a floating-point remainder.  
  
#include <math.h>  
#include <stdio.h>  
  
int main( void )  
{  
   double w = -10.0, x = 3.0, z;  
  
   z = fmod( w, x );  
   printf( "The remainder of %.2f / %.2f is %f\n", w, x, z );  
}  

The remainder of -10.00 / 3.00 is -1.000000  

Floating-Point Support
ceil, ceilf, ceill
fabs, fabsf, fabsl
floor, floorf, floorl
_CIfmod