class test
    {
        public static void Main(string[] args)
        {
            string s = "' ";
            MainClass y = new MainClass();
            BaseClass x = y;
            x.i = 100;
            Console.WriteLine("{0} ,{1}", x.i, y.i);
            Console.ReadKey();
        }

    }
    class MainClass : BaseClass
    {
        public int i;
    }

    class BaseClass
    {
        public int i;
    }