/*******************************************************
 Author: Francesco Taurisano (www.ftlaboratory.com)
 Parameters.cpp
 Parameter passing methods: by value and by reference
 *******************************************************/

#include <iostream>
using namespace std;

// Parameter passing by value
// a and b are formal parameters
void exchange1(int a, int b)
{
	int z;
	z=a;
	a=b;
	b=z;
}

// Parameter passing by reference (first way)
// a and b are formal parameters
void exchange2(int *a, int *b)
{
	int z;
	z=*a;
	*a=*b;
	*b=z;
}

// Parameter passing by reference (second way)
// a and b are formal parameters
void exchange3(int& a, int& b)
{
	int z;
	z=a;
	a=b;
	b=z;
}

int main()
{
  // Actual parameters
  // x and y are actual parameters
  int x, y;

  cout << "Parameter passing methods" << endl;
  cout << "Insert x ";
  cin >> x;
  cout << "Insert y ";
  cin >> y;
  
  // Parameter passing by value
  exchange1(x,y);

  // Show x and y
  cout << "Effect of parameter passing by value" << endl;
  cout << "x=" << x << endl;
  cout << "y=" << y << endl;

  // Parameter passing by reference (first way)
  exchange2(&x,&y);

  // Show x and y
  cout << "Effect of parameter passing by reference (first way)" << endl;
  cout << "x=" << x << endl;
  cout << "y=" << y << endl;

  // Parameter passing by reference (second way)
  exchange3(x,y);

  // Show x and y
  cout << "Effect of parameter passing by reference (second way)" << endl;
  cout << "Note: because this is the second inversion, the parameters return to their original values" << endl;
  cout << "x=" << x << endl;
  cout << "y=" << y << endl;
  system("pause");
  return 0;
}