#include <math.h>
double fmod (double x, double y);
float fmodf(float x, float y);
fmod() calculates the floating point remainder of x/y.
The floating point remainder of x/y, with the same sign as x. If y is 0, it returns 0 and sets errno to EDOM.
div()
ldiv()
ldexp() and ldexpf()
modf() and modff()