GNU/Linux man pages
Livre :
Expressions régulières,
Syntaxe et mise en oeuvre :
GNU/Linux |
CentOS 4.8 |
i386 |
 |
frexp(3) |
 |
frexp, frexpf, frexpl − convert floating-point number to fractional and integral components
#include <math.h>
double frexp(double x, int *exp);
float frexpf(float x, int *exp);
long double frexpl(long double x, int *exp);
The frexp() function is used to split the number x into a normalized fraction and an exponent which is stored in exp.
The frexp() function returns the normalized fraction. If the argument x is not zero, the normalized fraction is x times a power of two, and 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.
SVID 3, POSIX, BSD 4.3, ISO 9899. The float and the long double variants are C99 requirements.
#include
<stdio.h>
#include <math.h>
#include <float.h>
int main () {
double d = 2560;
int e;
double f = frexp(d, &e);
printf("frexp(%g, &e) = %g: %g * %d^%d =
%g\n",
d, f, f, FLT_RADIX, e, d);
return 0;
}
This program prints
frexp(2560, &e) = 0.625: 0.625 * 2^12 = 2560
ldexp(3), modf(3)
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frexp(3) | |