ldexpf

Multiply by integer power of 2

View other versions (4)

Contents

Interface
Description
Special Values
See Also
Standards
Page Comments

Interface

#include <math.h>double  ldexp (double x, int n)
long  ldexpl (long double x, int n)
float  ldexpf (float x, int n)

Description

The ldexp functions multiply x by 2 to the power of n.

Example:

Example - Multiply by integer power of 2

Workings

#include <stdio.h>
#include <math.h>
int main(void)
{
  double x = 3.14, result = ldexp(x, 10);
  printf("%.2lf * 2^10 = %.2lf\n", x, result);
  return 0;
}

Solution

Output:

3.14 * 2^10 = 3215.36

Special Values

ldexp (±0, n) returns ±0.

ldexp (±∞, n) returns ±∞.

Standards

The ldexp functions conform to ISO/IEC 9899:1999(E).

double	`ldexp` (double x, int n)
long	`ldexpl` (long double x, int n)
float	`ldexpf` (float x, int n)