Was this page helpful?
Your feedback about this content is important. Let us know what you think.
Additional feedback?
1500 characters remaining
Export (0) Print
Expand All
div
eof
Expand Minimize
Important This document may not represent best practices for current development, links to downloads and other resources may no longer be valid. Current recommended version can be found here.

modf, modff

Splits a floating-point value into fractional and integer parts.

double modf( 
   double x, 
   double *intptr  
); 
float modf( 
   float x, 
   float *intptr 
);  // C++ only 
long double modf( 
   long double x, 
   long double * intptr 
);  // C++ only 
float modff( 
   float x, 
   float *intptr  
);

x

Floating-point value.

intptr

Pointer to stored integer portion.

This function returns the signed fractional portion of x. There is no error return.

The modf function breaks down the floating-point value x into fractional and integer parts, each of which has the same sign as x. The signed fractional portion of x is returned. The integer portion is stored as a floating-point value at intptr.

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

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

Routine

Required header

modf, modff

<math.h>

For additional compatibility information, see Compatibility in the Introduction.

Libraries

All versions of the C run-time libraries.

// crt_modf.c

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

int main( void )
{
   double x, y, n;

   x = -14.87654321;      /* Divide x into its fractional */
   y = modf( x, &n );     /* and integer parts            */

   printf( "For %f, the fraction is %f and the integer is %.f\n", 
           x, y, n );
}

For -14.876543, the fraction is -0.876543 and the integer is -14

Community Additions

ADD
Show:
© 2015 Microsoft