#include <math.h>float rintf(float arg);double rint(double arg); long double rintl(long double arg);
rint( ), rintf( ), and rintl( ) were added by C99.
The rint( ) family of functions returns the value of arg rounded to the nearest integer. However, the number is returned as a floating-point value. It is possible that a floating-point exception will be raised.
Related functions are nearbyint( ), round( ), and rint( ).