/*Write a C# program to demonstrate multiple and Multi-level inheritance using abstract*/

using System;

using System.Collections;

​

interface IDevelopmentLanguage

{

    void languages();

}

​

class Developer1 : IDevelopmentLanguage

{

    public void languages()

    {

        ArrayList My_list = new ArrayList();

        My_list.Add("C");

        My_list.Add("C++");

        My_list.Add("C#");

        My_list.Add("Java");

        Console.WriteLine("Languages provided for Development:");

        foreach (var elements in My_list)

        {

            Console.WriteLine(elements);

        }

    }

}

​

public abstract class IDevelopmentCourse

{

    public abstract void courses();

}

​

class Developer2 : IDevelopmentCourse

{

    protected ArrayList My_list = new ArrayList();

    public override void courses()

    {

        My_list.Add("System Design");

        My_list.Add("Python Jam");

        My_list.Add("Classes on DSA");

        My_list.Add("Java Fullstack");

        Console.WriteLine("\nCourses provided for Development:");

        foreach (var elements in My_list)

        {

            Console.WriteLine(elements);

        }

    }

}

​

class Development : Developer2,IDevelopmentLanguage 

{

    Developer1 developer1 = new Developer1();

    public void languages()

    {

        developer1.languages();

    }

​

    public new void courses()

    {

        base.courses();

    }

}

​

public class Program

{

    public static void Main()

    {

        Development development = new Development();

        development.languages();

        development.courses();

    }

}