Synopsis
#include <math.h>
double floor(double x);
Description
floor computes the largest integer value not greater than x.
IEC 60559 math library behavior
floor(±0) is±0.
floor(±∞) is ±∞.
Portability
floor conforms to ISO/IEC 9899:1990 (C90) and ISO/IEC 9899:1999 (C99).