NAME
frexp, frexpf, frexpl - convert floating-point number to fractional
and integral components
SYNOPSIS
#include <math.h>
I double frexp(double x , int * exp );
I float frexpf(float x , int * exp );
I long double frexpl(long double x , int * exp );
Link with
-lm.
DESCRIPTION
The
R frexp ()
function is used to split the number x into a
normalized fraction and an exponent which is stored in exp.
RETURN VALUE
The
R frexp ()
function returns the normalized fraction.
If the argument x is not zero,
the normalized fraction is x times a power of two,
and its absolute value is always in the range 1/2 (inclusive) to
1 (exclusive).
If x is zero, then the normalized fraction is
zero and zero is stored in exp.
CONFORMING TO
SVr4, 4.3BSD, C89.
The
float
and
long double
variants are C99 requirements.
EXAMPLE
#include <math.h>
#include <float.h>
#include <stdio.h>
#include <stdlib.h>
int
main(int argc, char *argv[])
{
double x, r;
int exp;
x = strtod(argv[1], NULL);
r = frexp(x, &exp);
printf("frexp(%g, &e) = %g: %g * %d^%d = %g\n",
x, r, r, FLT_RADIX, exp, x);
exit(EXIT_SUCCESS);
} /* main */
This program produces results such as the following:
$ ./a.out 2560
frexp(2560, &e) = 0.625: 0.625 * 2^12 = 2560
$ ./a.out -4
frexp(-4, &e) = -0.5: -0.5 * 2^3 = -4
SEE ALSO
ČLÁNKY DO MAILU