# include <stdlib.h>
# include <stdio.h>
# include <math.h>

int main ( )
{
  double a;
  double b;
  int i;
  int it;
  double tol = 1.0E-10;
  double w;
  double w_vec[8] = {
    0.3517337112491958, 
    0.5671432904097839, 
    0.7258613577662263, 
    0.8526055020137255, 
    0.9585863567287029, 
    0.1000000000000000E+01, 
    0.1745528002740699E+01, 
    0.3385630140290050E+01 };
  double x;
  double x_vec[8] = {
    0.5000000000000000, 
    0.1000000000000000E+01, 
    0.1500000000000000E+01, 
    0.2000000000000000E+01, 
    0.2500000000000000E+01, 
    0.2718281828459045E+01, 
    0.1000000000000000E+02, 
    0.1000000000000000E+03 };

  for ( i = 0; i < 8; i++ )
  {
    x = x_vec[i];
    w = x + log ( x );

    it = 0;

    while ( 1 )
    {
      if ( 100 < it )
      {
        break;
      }

      if ( fabs ( ( x - w * exp ( w ) ) ) < 
        tol * fabs ( ( w + 1.0 ) * exp ( w ) ) )
      {
        break;
      }
      a = w * exp ( w ) - x;
      b = ( w + 1.0 ) * exp ( w ) 
        - ( w + 2.0 ) * ( w * exp ( w ) - x ) / ( 2.0 * w + 2.0 );
      w = w - a / b;
      it = it + 1;
    }
    printf ( "  %8.4f  %3d  %14g  %14g  %8.2e\n",
      x, it, w, w_vec[i], fabs ( w - w_vec[i] ) );
  }
  return 0;
}