#include <iostream>
using namespace std;

/*
  Illustrates the difference between a value parameter and a 
  reference parameter.
*/

int squareVal( int i )   // This function has its own local 
{                        // storage for its parameter, i.  This storage is
  i *= i;                // NOT accessible to any other function.
  return i;
}

int squareRef( int& i )  // This function shares the storage with
{                        //  the calling program for its parameter, i.
  i *= i;            
  return i;
}

int main( ){
   int j = 2;
   cout << "Initially, j == " << j << ".\n";

   cout << "squareVal(j) == " << squareVal(j) << ".\n";
   cout << "After the call to squareVal(), j == " << j << ".\n";

   cout << "squareRef(j) == " << squareRef(j) << ".\n";
   cout << "After the call to squareRef(), j == " << j << ".\n";

   return 0;
}

/*  Output:

Initially, j == 2.
squareVal(j) == 4.
After the call to squareVal(), j == 2.
squareRef(j) == 4.
After the call to squareRef(), j == 4.

*/