ldexp


function
<cmath>
     double ldexp (      double x, int exp );
      float ldexp (       float x, int exp );
long double ldexp ( long double x, int exp );

Generate number from significand and exponent

Returns the resulting floating point value from multiplying x (the significand) by 2 raised to the power of exp (the exponent).

Parameters

x
Floating point value representing the significand.
exp
Value of the exponent.


Return Value

The function returns:

x * 2 exp

Portability

In C, only the double version of this function exists with this name.

Example

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/* ldexp example */
#include <stdio.h>
#include <math.h>

int main ()
{
  double param, result;
  int n;

  param = 0.95;
  n = 4;
  result = ldexp (param , n);
  printf ("%f * 2^%d = %f\n", param, n, result);
  return 0;
}


Output:

0.950000 * 2^4 = 15.200000


See also

frexp Get significand and exponent (function)
log Compute natural logarithm (function)
pow Raise to power (function)