using System;

​

namespace ConsoleApp4

{

    public class Program

    {

        public static void Main(string[] args)

        {

            B x = new B();

            x.show();

        }

    }

​

    public class A     //base class

    {

        protected virtual int no => 1;

​

        public void show()

        {

            Console.WriteLine(no);

        }

    }

    public class B : A  //sub class

    {

        protected override int no => 100;

    }

}