Memory efficient power set algorithm

Question

Trying to calculate all the subsets (power set) of the 9-letter string \'ABCDEFGHI\'.

Using standard recursive methods, my machine hits out of memory (1GB) error bef

Answer 1

I verified that this worked well:

#include 

void print_combination(char* str, char* buffer, int len, int num, int pos)
{
  if(num == 0)
  {
    std::cout << buffer << std::endl;
    return;
  }

  for(int i = pos; i < len - num + 1; ++i)
  {
    buffer[num - 1] = str[i];
    print_combination(str, buffer, len, num - 1, i + 1);
  }
}

int main()
{
  char str[] = "ABCDEFGHI";
  char buffer[10];
  for(auto i = 1u; i <= sizeof(str); ++i)
  {
    buffer[i] = '\0';
    print_combination(str, buffer, 9, i, 0);
  }
}