#include <iostream>

using namespace std;

//Pre-declaration of function mySwap. 
//Proving parameter names is optional here. But data types are required.
void mySwap(int & x, int & y);

int main()
{
	int a = 10;
	int b = 20;

	cout << "Before swap a= " << a << "   b=" << b << endl;

	mySwap(a, b);

	cout << "After  swap a= " << a << "   b=" << b << endl;
	
	return 0;
}

void mySwap(int & x, int & y)
{
	int temp;

	temp = x;   //Coke to an empty cup
	x = y;		//Pepsi to Coke's cup
	y = temp;	//Coke to Pepis's cup
}

//Before swap a= 10   b=20
//After  swap a= 20   b=10
//Press any key to continue . . .