#include <iostream>  

using namespace std;

void Twice(int&, int&);			// DECLARE before use

int main()
{
	int x = 5, y = 8;

	cout << "Initial values of variables:\n";
	cout << "\tx = ";
	cout << x;
	cout << "\ty = ";
	cout << y;
	cout << '\n';

	cout << "Calling the function Twice(x,y)\n";

	Twice(x,y);
	
	cout << "The new values of x and y are:\n";
	cout << "\tx = " << x << "\ty = " << y << '\n';
	cout << "Goodbye!\n";
}

void Twice(int& a, int& b)
{
	a *= 2;
	b *= 2;
}