#include <iostream.h>

// file: ref.cc; author: D. Ramm; date: 10/22/96
// function to play with ref parameters

Manip(int & x, int & y)
{
   x += y;
   y += x;
}

int main()
{
   int a, b;

   a = 2; b = 3;

   cout << "Before: a = " << a << " b = " << b << endl;
   Manip(a, b);
   cout << "After: a = " << a << " b = " << b << endl;
   cout << endl;

   a = 2; b = 3;
   cout << "Before: a = " << a << " b = " << b << endl;
   Manip(b, a);
   cout << "After: a = " << a << " b = " << b << endl;
   cout << endl;

   a = 2; b = 3;
   cout << "Before: a = " << a << " b = " << b << endl;
   Manip(b, b);
   cout << "After: a = " << a << " b = " << b << endl;

   return 0;
}

Sample output:
ref
Before: a = 2 b = 3
After: a = 5 b = 8

Before: a = 2 b = 3
After: a = 7 b = 5

Before: a = 2 b = 3
After: a = 2 b = 12