// ptr17.cpp 		By: Aiman Hanna -  ©1993-2006 Aiman Hanna

// This program is a simple example of the use of References. In specific, 
// the program shows how references and pointers could be related


//	Key Points: References and Pointers

#include <iostream.h>
#include <string.h>

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


void RealSwapByPointer( int *a, int *b )
{
    int tmp = *a;
    *a = *b;
    *b = tmp;
}


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



int main()
{
 int x = 10, y = 7;
 int *x_ptr = &x, *y_ptr = &y;
 cout <<  " x is: " << x << "\n";
 cout << " y is: " << y << "\n";

 UselessSwap( x , y );
 cout << " The value of x after Useless Swap is: " << x << "\n";
 cout << " The value of y after Useless Swap is: " << y << "\n\n";

 RealSwapByPointer( x_ptr , y_ptr );
 cout << " The value of x after Swap using Pointers is: " << x << "\n";
 cout << " The value of y after Swap using pointers is: " << y << "\n\n";

 RealSwapByReference( x , y );
 cout << " The value of x after Swap using References is: " << x << "\n";
 cout << " The value of y after Swap using References is: " << y << "\n";
 return 0;
}


// The following is the result of running the program

/*
 x is: 10
 y is: 7
 The value of x after Useless Swap is: 10
 The value of y after Useless Swap is: 7

 The value of x after Swap using Pointers is: 7
 The value of y after Swap using pointers is: 10

 The value of x after Swap using References is: 10
 The value of y after Swap using References is: 7
*/