floor, floorf, floorl

發行項
06/05/2017

The new home for Visual Studio documentation is Visual Studio 2017 Documentation on docs.microsoft.com.

The latest version of this topic can be found at floor, floorf, floorl.

Calculates the floor of a value.

Syntax

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

Parameters

x
Floating-point value.

Return Value

The floor functions return a floating-point value that represents 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). For information and restrictions about using the SSE2 implementation, see _set_SSE2_enable.

Remarks

C++ allows overloading, so you can call overloads of floor that take and return float and long double values. In a C program, floor always takes and returns a double.

Requirements

Function	Required header
`floor`, `floorf`, `floorl`	<math.h>

For additional compatibility information, see Compatibility.

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 );  
}

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

.NET Framework Equivalent

System::Math::Floor

共用方式為