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floor, floorf

Calculates the floor of a value.

double floor(
   double x
);
float floor(
   float x 
); // C++ only
long double floor(
   long double x
); // C++ only
float floorf(
   float x
);

Parameter

x
Floating-point value.

Return Value

The floor function returns a floating-point value representing the largest integer that is less than or equal to x. There is no error return.

Input SEH Exception Matherr Exception
± QNAN,IND none _DOMAIN

floor has an implementation that uses Streaming SIMD Extensions 2 (SSE2). See _set_SSE2_enable for information and restrictions on using the SSE2 implementation.

Remarks

C++ allows overloading, so you can call overloads of floor. In a C program, floor always takes and returns a double.

Requirements

Function Required header Compatibility
floor, floorf <math.h> ANSI, Win 98, Win Me, Win NT, Win 2000, Win XP

For additional compatibility information, see Compatibility in the Introduction.

Libraries

All versions of the C run-time libraries.

Example

// crt_floor.c
/* This example displays the largest integers
 * less than or equal to the floating-point values 2.8
 * and -2.8. It then shows the smallest integers greater
 * than or equal to 2.8 and -2.8.
 */

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

int main( void )
{
   double y;

   y = floor( 2.8 );
   printf( "The floor of 2.8 is %f\n", y );
   y = floor( -2.8 );
   printf( "The floor of -2.8 is %f\n", y );

   y = ceil( 2.8 );
   printf( "The ceil of 2.8 is %f\n", y );
   y = ceil( -2.8 );
   printf( "The ceil of -2.8 is %f\n", y );
}

Output

The floor of 2.8 is 2.000000
The floor of -2.8 is -3.000000
The ceil of 2.8 is 3.000000
The ceil of -2.8 is -2.000000

See Also

Floating-Point Support Routines | ceil | fmod | Run-Time Routines and .NET Framework Equivalents

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