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modf, modff, modfl

 

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The latest version of this topic can be found at modf, modff, modfl.

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   
);  
long double modfl(  
   long double x,  
   long double * intptr  
);  

Parameters

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 functions break 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 that take and return float or long double parameters. In a C program, modf always takes two double values and returns a double value.

RoutineRequired header
modf, modff, modflC: <math.h>

C++: , <cmath> or <math.h>

For additional compatibility information, see Compatibility in the Introduction.

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  

Floating-Point Support
frexp
ldexp

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