Calculates the double value corresponding to the largest integer that is less than or equal to x.
double floor( double x )
floor(x)
EX1
void floor_ex1() { double x1 = -4.6, x2 = 4.6; printf("floor(%f) = %f\nfloor(%f) = %f\n", x1, floor(x1), x2, floor(x2)); }
ceil
origin.h