C Standard Library
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C <math.h> - ldexp() Function

The C <math.h> ldexp() function returns the result of multiplying the significand (x) by 2 raised to the power of the exponent (exp), i.e., x * 2exp.


double ldexp (double x, int exp);
float ldexpf (float x, int exp);
long double ldexpl (long double x, int exp);


x Specify floating point value representing the significand.
exp Specify value of the exponent.

Return Value

Returns x * 2exp.


The example below shows the usage of ldexp() function.

#include <stdio.h>
#include <math.h>
int main (){
  double x, result;
  int y;
  x = 0.9;
  y = 4;

  result = ldexp(x, y);

  printf("Significand: %lf\n", x);
  printf("Exponent: %d\n", y);
  printf("Result: %lf\n", result);

  return 0;

The output of the above code will be:

Significand: 0.900000
Exponent: 0.900000
Result: 14.400000

❮ C <math.h> Library