#include <cmath>
    double modf( double num, double *i );

The function modf() splits num into its integer and fraction parts. It returns the fractional part and loads the integer part into i.

C++ also provides the following overloaded forms:

    #include <cmath>
    float modf( float num, float *i ); // same as modff() in C99
    long double modf( long double num, long double *i ); // same as modfl() in C99

Related Topics: frexp, ldexp