#include <iostream>
using namespace std;

// pass by value (only copy swapped)
void mySwap(int a, int b){
	int t = a;
	a = b;
	b = t;
   cout << a << " " << b << endl;
}
// pass by reference (data in main swapped)
void mySwapR(int &a, int &b){
	int t = a;
	a = b;
	b = t;
   cout << a << " " << b << endl;
}
// pass by pointer (data in main swapped)
void mySwapP(int *a, int *b){
	int t = *a;
	*a = *b;
	*b = t;
   cout << *a << " " << *b << endl;
}


void main(){
   int x = 1, y = 17;
   double d = 3.14159;
   double &rd = d;
   rd = -4.789;
   cout << &rd << " " << &d << endl;
   cout << d << endl;
   mySwap(x, y);
   cout << x << " " << y << endl;
   mySwapP(&x, &y);
   cout << x << " " << y << endl;
   mySwapR(x, y);
   cout << x << " " << y << endl;
}