//------------------------------------------------------
//
// swap.cpp
//
// The classic program to illustrate reference parameters.
//
// Written by: Simon Parsons
// 27th October 2008
//
//------------------------------------------------------

// Header files and namespace.

#include <iostream>
using namespace std;


// Function prototypes

void swap( int &a, int &b );
void notswap( int a, int b );


// Main program

int main() 
{
  int x = 5;
  int y = 7;

  // With reference parameters we swap the values of x and y.

  cout << "Before swap: x = " << x << " y = " << y << endl;
  swap( x, y );
  cout << "...after swap: x = " << x << " y = " << y << endl;

  // Without reference parameters, we don't swap x and y.

  cout << "Let's try that again" << endl;

  x = 23;
  y = 6;

  cout << "Before swap: x = " << x << " y = " << y << endl;
  notswap( x, y );
  cout << "...after swap: x = " << x << " y = " << y << endl;

} 

// Declare function swap(), using reference parameters
// This one swaps the variable values.

void swap( int &a, int &b ) 
{
  int tmp;
  tmp = a;
  a = b;
  b = tmp;
  return;
}


// Declare function notswap()
// This does not swap the values.

void notswap( int a, int b ) 
{
  int tmp;
  tmp = a;
  a = b;
  b = tmp;
  return;
}