modf, modff, modfl
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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.
| Routine | Required header |
|---|---|
modf, modff, modfl | C: <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