floor : <math.h> library function

The function double floor(double x); returning the largest integral value less than or equal to x.

Function prototype of floor

double floor(double x);
  • x : A floating point value to round down.

Return value of floor

It returns the largest integral value less than or equal to x.

C program to show the use of floor function

The following program shows the use of floor function to round down value of x.

#include <stdio.h>
#include <math.h>

int main ()
{
  double x, result;
  printf("Enter a number\n");
  scanf("%lf", &x);
  
  result = floor(x);
  printf("Largest integer <= of %lf is %lf\n", x, result);
  
  return 0;
}

Program Output
Enter a number
2.3
Largest integer <= of 2.300000 is 2.000000
Enter a number
-2.3
Largest integer <= of -2.300000 is -3.000000