floor

Round to largest integral value not greater than x

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Contents

Interface
Description
Special Values
See Also
Standards
Page Comments

Interface

#include <math.h>double  floor (double x)
long  floorl (long double x)
float  floorf (float x)

Description

The floor functions return the largest integral value less than or equal to x.

Example:

Example - Round to largest integral value not greater than x

Workings

#include <stdio.h>
#include <math.h>
 
int main(void)
{
  for (double a = 12.5; a < 13.4; a += 0.1)
    printf("floor of  %.1lf is  %.1lf\n", a, floor(a));
  return 0;
}

Solution

Output:

floor of  12.5 is  12.0
floor of  12.6 is  12.0
floor of  12.7 is  12.0
floor of  12.8 is  12.0
floor of  12.9 is  12.0
floor of  13.0 is  13.0
floor of  13.1 is  13.0
floor of  13.2 is  13.0
floor of  13.3 is  13.0
floor of  13.4 is  13.0

Special Values

floor ( ±0 ) returns ±0.

floor ( ±∞ ) returns ±∞.

Standards

The floor functions conform to ISO/IEC 9899:1999(E).

double	`floor` (double x)
long	`floorl` (long double x)
float	`floorf` (float x)