prac 18 x2

using System;

abstract public class Edition
{
    abstract public void Show();
    public bool IsDesired(string a)
    {
        if (author_surname == a) return true; else return false;
    }
    protected string name;
    protected string author_surname;
    protected int year;
}

public class Book: Edition
{
    protected string editor;
    public Book()
    {
    }
    public Book (string name, string author_surname, int year, string editor)
    {
        this.name = name;
        this.author_surname = author_surname;
        this.year = year;
        this.editor = editor;
    }
    public override void Show()
    {
        Console.WriteLine("{0}, {1}, {2}, {3}.", name, author_surname, year, editor);
    }

}

public class Article: Edition
{
    protected string mag_name;
    protected int num_mag;


}

public class EResource: Edition
{
    protected string link;
    protected strinh annotation;
}

public class Program
{
    public static void Main()
    {
        Console.WriteLine("Hello World");
    }
}