Computes a real number from the mantissa and exponent.
double ldexp( double x, int exp );
| Routine | Required Header | Compatibility |
| ldexp | <math.h> | ANSI, Win 95, Win NT |
For additional compatibility information, see Compatibility in the Introduction.
Libraries
| LIBC.LIB | Single thread static library, retail version |
| LIBCMT.LIB | Multithread static library, retail version |
| MSVCRT.LIB | Import library for MSVCRT.DLL, retail version |
Return Value
The ldexp function returns the value of x * 2exp if successful. On overflow (depending on the sign of x), ldexp returns +/– HUGE_VAL; the errno variable is set to ERANGE.
Parameters
x
Floating-point value
exp
Integer exponent
Example
/* LDEXP.C */
#include <math.h>
#include <stdio.h>
void main( void )
{
double x = 4.0, y;
int p = 3;
y = ldexp( x, p );
printf( "%2.1f times two to the power of %d is %2.1f\n", x, p, y );
}
Output
4.0 times two to the power of 3 is 32.0