#include <iostream.h>

// space over some to show how deep we are in recursion
void space (int num){
   const int max_space = 10;
   // space more when number is lower - thats when we are deeper
   int times = max_space - num;
   // go over three spaces for each 
   for (int cnt = 0; cnt < times; cnt++) {
      cout << "   ";
    }
 }

// recursively calculate factorial
int Factorial(int n){
   cout << endl;
   space(n);
   cout << "in factorial with n = " << n << endl; 
   // termination part - time to stop recursion
   //   0! is defined to be 1
   if (n == 0){
      cout << endl;
      space(n);
      cout << "ending factorial with n = " << n << " and result = 1" << endl; 
      return 1;
     }
   // bigger number - n! is n * (n - 1)!
   //    (recurse on smaller number)
   else {
      int result = n * Factorial(n - 1);
      cout << endl;
      space(n);
      cout << "ending factorial with n = " << n << " and result = "
           << result << endl; 
      return result;
   }
 }

// try recursive factorial function out for 5
int main() {
   cout << "The result for 5 factorial" << endl;
   int res = Factorial(5);
   cout << "   is: " << res << endl;
   return 0;
 }