All permutations

#include <iostream>

using namespace std;

static int permutations = 0;

void permute(string src, string permutation){
  if(src.length() == 0){
    cout << permutation << endl;
    permutations++;
    return;
  }
  for(int i = 0; i < src.length(); i++){
    string newSrc = src.substr(0 ,i) + src.substr(i+1, src.length() - (i + 1));
    permute(newSrc, permutation + src[i]);
  }
}

void permute(string src){
  permute(src, "");
}

int main()
{
    permute("1234");
    cout << "Number of permutations: " << permutations << endl;
    return 0;
}