using System;

public class Program

{

        //1. 'ref' is a keyword that allows us to pass simple data types by reference

        //2. Whatever changes are made to x and y inside Swap are also visible inside Main

        //3. This is NOT how double data types normally behave

        static void Swap(ref double x, ref double y)

        {

            double temp = x; //4. Saves x to a temporary holding location

            x = y; //5. Stores the values of y to x

            y = temp; //6. Stores the value of temp, which is really the value of x, to y

        }

        public static void Main()

        {

    }

}