#include <stdio.h>

#include <gsl/gsl_combination.h>

int 

main (void) 

{

  gsl_combination * c;

  size_t i;

  printf ("All subsets of {0,1,2,3} by size:\n") ;

  for (i = 0; i <= 4; i++)

    {

      c = gsl_combination_calloc (4, i);

      do

        {

          printf ("{");

          gsl_combination_fprintf (stdout, c, " %u");

          printf (" }\n");

        }

      while (gsl_combination_next (c) == GSL_SUCCESS);

      gsl_combination_free (c);

    }

  return 0;

}