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modf

From cppreference.com
< c‎ | numeric‎ | math
 
 
 
Common mathematical functions
Functions
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(C99)(C99)(C99)
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Trigonometric and hyperbolic functions
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Nearest integer floating point operations
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Floating point manipulation functions
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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

[edit] Parameters

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

[edit] 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.

[edit] 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);
}

Possible output:

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

[edit] See also

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