using System;

public class Program

{

    public static void Main()

    {

        BaseClass objBaseDerivedClass = new DerivedClass();

        Console.WriteLine("First Name : " + objBaseDerivedClass.FirstName);

        objBaseDerivedClass.LastName = "own last name";

        Console.WriteLine("Last Name : " + objBaseDerivedClass.LastName);

    }

public class BaseClass

{

    public string FirstName = "Base Class";

}

​

public class DerivedClass : BaseClass

{

    public string LastName = "Base Class";

    public DerivedClass()

    {

    }

}

​

}