C/math.h/floor
floor: returns the largest integer (represented as a floating-point value) not greater than num
//Declaration: float floorf(float num);
double floor(double num);
long double floorl(long double num);
//Return: Given 1.02, floor() would return 1.0.
Given -1.02, floor() would return -2.0.
#include <math.h>
#include <stdio.h>
int main(void)
{
printf("%f", floor(10.9));
}
/*
10.000000*/