using System;

using System.Collections.Generic;

​

public class Program

{

    public static void Main()

    {

        Console.WriteLine("Welcome to Book creator!");

        Console.WriteLine("Would you like to make a Novel or History book?");

        string bookType = Console.ReadLine();

        BookFactory bookFactory = new CoolBookFactory(bookType);

        Book userBook = bookFactory.Create();

        // The magic of the pattern is below:

        Console.WriteLine("PAGES -----");

        foreach (var page in userBook.pages)

        {

            Console.WriteLine(page.GetType().Name);

        }

    }

}

​

abstract class BookFactory

{

    public abstract Book Create();

}

​

class CoolBookFactory : BookFactory

{

    public string BookType { get; private set; }

​

    public CoolBookFactory(string bookType)

    {

        this.BookType = bookType;

    }

​

    public override Book Create()

    {

        if (this.BookType == "Novel")

            return new NovelBook();

        if (this.BookType == "History")

            return new HistoryBook();

​

        return null;

    }

}

​

abstract class Book

{

    public List<Page> pages = new List<Page>();

}

​

class NovelBook : Book 

{

    public NovelBook()

    {

        this.pages.Add(new TitlePage());

        this.pages.Add(new EventPage());

        this.pages.Add(new AboutTheAuthorPage());

    }

}

​

class HistoryBook : Book

{

    public HistoryBook()

    {

        this.pages.Add(new AcknowledgmentsPage());

        this.pages.Add(new UnitsPage());

        this.pages.Add(new GlossaryPage()); 

    }

}

​

abstract class Page {}

class TitlePage : Page {}

class EventPage : Page {} 

class AboutTheAuthorPage : Page {}

class AcknowledgmentsPage: Page {}

class UnitsPage : Page {} 

class GlossaryPage : Page {}