// program 6.5: Demonstrate call by reference
#include <iostream>
using namespace std;
void Mystery(int a, int &b) {
    cout << "Output at beginning of Mystery" << endl;
    cout << "a is " << a << endl;
    cout << "b is " << b << endl;
    a = 5;
    b = 6;
    cout << "Output after Mystery assignments" << endl;
    cout << "a is " << a << endl;
    cout << "b is " << b << endl;
    return;
}

int main() {
   int i = 10;
   int j = 20;
   cout << "Output at beginning of main" << endl;
   cout << "i is " << i << endl;
   cout << "j is " << j << endl;
   Mystery(i, j);
   cout << "Output after Mystery returns" << endl;
   cout << "i is " << i << endl;
   cout << "j is " << j << endl;
   return 0;
}