using System;

​

namespace Program

{

    public class Program

    {   

        public static void Main(string[] args)

        {

            var foo = new Foo();

            foo.Bar = 5;

            ref int bar = ref foo.Bar;

            Console.WriteLine(foo.Bar);

            Console.WriteLine(bar);

            foo.Bar = 6;

            Console.WriteLine(foo.Bar);

            Console.WriteLine(bar);

            bar = 7;

            Console.WriteLine(foo.Bar);

            Console.WriteLine(bar);

        }

    }

}

​

class Foo{

    public int Bar;

}

​