#include <stdio.h>

#include <gsl/gsl_math.h>

#include <gsl/gsl_ieee_utils.h>

int

main (void)

{

  double x = 1, oldsum = 0, sum = 0; 

  int i = 0;

  gsl_ieee_env_setup (); /* read GSL_IEEE_MODE */

  do 

    {

      i++;

      oldsum = sum;

      sum += x;

      x = x / i;

      printf ("i=%2d sum=%.18f error=%g\n",

              i, sum, sum - M_E);

      if (i > 30)

         break;

    }  

  while (sum != oldsum);

  return 0;

}