/* test_combinations.c  generate all combinations of n things taken m */
/*                      at a time */



#include <stdlib.h>
#include <stdio.h>
#include "combinations.h"
/* last = combinations(n, m, vn[], vm[], &first);                          */
/* return is 0 if more combinations to come. 1 if this is last             */
/* n is for n things     n! / ((n-m)! m!) combinations                     */
/* m is for m at a time                                                    */
/* vn must be the n items, unchanged by comb (can by pointers or indices)  */
/* vm must be of size m items, the returned combination each call          */
/* first must be 1 the first call, then set to zero internally             */

int main(int argc, char *argv[])
{
  int n, m, first, last;
  int v3[4] = {1, 2, 3, 4};
  int v2[2];
  int v6[6] = {1, 2, 3, 4, 5, 6};
  int v[6];
  int i;
  
  printf("test_combinations.c running \n");
  first = 1;
  last = 0;
  n = 4;
  m = 2;
  while(!last)
  {
    last = combinations(n, m, v3, v2, &first);
    printf("combinations(n=%d, m=%d, last=%d, %d %d \n",
           n, m, last, v2[0], v2[1]);
  }
  printf("\n");
  
  first = 1;
  last = 0;
  n = 6;
  m = 3;
  while(!last)
  {
    last = combinations(n, m, v6, v3, &first);
    printf("combinations(n=%d, m=%d, last=%d, %d %d %d \n",
           n, m, last, v3[0], v3[1], v3[2]);
  }
  printf("\n");

  printf("many cases n=6, m=0 to 7 \n");
  n = 6;
  for(m=0; m<=7; m++)
  {
    first = 1;
    last = 0;
    while(!last)
    {
      last = combinations(n, m, v6, v, &first);
      printf("combinations(n=%d, m=%d,  %d", n, m, v[0]);
      for(i=1; i<m; i++) printf(" %d", v[i]);
      printf("\n");
    }
    printf("\n");
  }
  printf("check unchanged v6=%d %d %d %d %d %d\n",
         v6[0], v6[1], v6[2], v6[3], v6[4], v6[5]);
  printf("end test_combinations.c \n");
  return 0;
} /* end test_combinations.c */