Namespaces
Variants
Views
Actions

modf

From cppreference.com
< c‎ | numeric‎ | math
Revision as of 13:59, 10 May 2014 by Newatthis (Talk | contribs)

 
 
 
Common mathematical functions
Functions
Basic operations
(C99)
(C99)
(C99)
(C99)
(C99)
(C99)(C99)(C99)
Exponential functions
(C99)
(C99)
(C99)
(C99)
Power functions
(C99)
(C99)
Trigonometric and hyperbolic functions
(C99)
(C99)
(C99)
Error and gamma functions
(C99)
(C99)
(C99)
(C99)
Nearest integer floating point operations
(C99)(C99)(C99)
(C99)
(C99)(C99)(C99)
Floating point manipulation functions
(C99)(C99)
(C99)
(C99)
modf
Classification
(C99)
(C99)
(C99)
Macro constants
 
Defined in header <math.h>
float       modff( float arg, float* iptr );
(since C99)
double      modf( double arg, double* iptr );
long double modfl( long double arg, long double* iptr );
(since C99)

Decomposes given floating point value arg into integral and fractional parts, each having the same type and sign as arg. The integral part (in floating-point format) is stored in the object pointed to by iptr.

Contents

Parameters

arg - floating point value
iptr - pointer to floating point value to store the integral part to

Return value

The fractional part of arg with the same sign as arg. The integral part is put into the value pointed to by iptr.

Example

#include <stdio.h>
#include <math.h>
 
int main(void)
{
    double whole,fract;
    fract = modf(+1.5,&whole);
    printf("%+4.0f   %+f\n", whole,fract);
    fract = modf(-1.5,&whole);
    printf("%+4.0f   %+f\n", whole,fract);
    fract = modf(+INFINITY,&whole);
    printf("%+4.0f   %+f\n", whole,fract);
    fract = modf(-INFINITY,&whole);
    printf("%+4.0f   %+f\n", whole,fract);
    fract = modf(+NAN,&whole);
    printf("%+4f   %+f\n", whole,fract);
    fract = modf(-NAN,&whole);
    printf("%+4f   %+f\n", whole,fract);
 
    return 0;
}

Possible output:

+1   +0.500000
  -1   -0.500000
+inf   +0.000000
-inf   -0.000000
+nan   +nan
-nan   -nan

See also

(C99)(C99)(C99)
rounds to nearest integer not greater in magnitude than the given value
(function) [edit]