floor() —Find Integer <=Argument

Format

#include <math.h>
double floor(double x);

Language Level: ANSI

Threadsafe: Yes.

Description

The floor() function calculates the largest integer that is less than or equal to x.

Return Value

The floor() function returns the floating-point result as a double value.

The result of floor() cannot have a range error.

Example that uses floor()

This example assigns y the value of the largest integer less than or equal to 2.8 and z the value of the largest integer less than or equal to -2.8.

#include <math.h>
#include <stdio.h>
 
int main(void)
{
   double y, z;
 
   y = floor(2.8);
   z = floor(-2.8);
 
   printf("floor(  2.8 ) = %lf\n", y);
   printf("floor( -2.8 ) = %lf\n", z);
}
/*******************  Output should be similar to:  ***************
 
floor(  2.8 ) = 2.000000
floor( -2.8 ) = -3.000000
*/

Related Information

• ceil() — Find Integer >=Argument
• fmod() — Calculate Floating-Point Remainder
• <math.h>