choose m element from n-set

combine.c

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

void combine(int src[], int s, int e, int k, int take[], int p)
{
  

  if(k == e - s + 1) {
    
    for(int i = 0; i < p; i++)
      printf("%d,",take[i]);
    for(int i = s; i <= e; i++)
      printf("%d,",src[i]);
    
    printf("\n");
    return ;
  }

  else if(k == 1) {

    for(int i = s; i <= e; i++) {
      for(int j = 0; j < p; j++)
    printf("%d,",take[j]);

      printf("%d\n",src[i]);
    }
    return ;
  }
  
  else {
    int i = p;

    take[i++] = src[s];
    combine(src, s+1, e, k-1, take, i);

    combine(src, s+1, e, k, take, p);
    
  }

}

int main() 
{
  int a[9] = {1,2,3,4,5,8,9,10,11};
  int b[3] = {0};

  combine(a,0,8,3,b,0);
}