//###############################################################################
// A recursive function to find the index of the minimum number in an array.
// Denote the array by a[0..size-1], where "0..size-1" is the range of the valid
// index.
// The idea is to find out the index of the minimum number is a[0..size-2]. In
// other words we solve the same problem for a slightly smaller problem. That
// minimum number is then compared with a[size-1], and the index of the smaller
// number is the solution.
// The base case is when the size of array is 1, in which case, the result is
// obviously 0.
//###############################################################################
#include <stdio.h>

int recursive_find_min(int a[], int size)
{
   if(size == 1)
      return 0;
   else {
      int idx = recursive_find_min(a, size-1);
      if(a[idx] <= a[size-1])
         return idx;
      else
         return size-1;
   }
}

int main()
{
    int a[] = {9,6,8,4,7};
    printf("%d\n", recursive_find_min(a, sizeof(a)/sizeof(a[0])));
}