C# - Äpfel und Birnen

using System;
using System.Collections.Generic;

namespace AepfelUndBirnen
{
    /// <summary>
    /// http://de.wikipedia.org/wiki/Bedecktsamer
    /// </summary>
    public abstract class Magnoliopsida 
    {
        public String Name;
    }

    /// <summary>
    /// http://de.wikipedia.org/wiki/Rosenartige
    /// </summary>
    public abstract class Rosales : Magnoliopsida { }

    /// <summary>
    /// http://de.wikipedia.org/wiki/Rosengew%C3%A4chse
    /// </summary>
    public abstract class Rosaceae : Rosales { }

    /// <summary>
    /// http://de.wikipedia.org/wiki/Spiraeoideae
    /// </summary>
    public abstract class Spiraeoideae : Rosaceae { }

    /// <summary>
    /// http://de.wikipedia.org/wiki/Pyreae
    /// </summary>
    public abstract class Pyreae : Spiraeoideae { }

    /// <summary>
    /// http://de.wikipedia.org/wiki/Kernobstgew%C3%A4chse
    /// </summary>
    public abstract class Pyrinae : Pyreae, IComparable<Pyrinae>
    {
        public UInt16 AnzahlKerne;

        public Int32 CompareTo(Pyrinae other)
        {
            if (other == null)
            {
                return (1);
            }
            return (this.AnzahlKerne.CompareTo(other.AnzahlKerne));
        }
    }

    /// <summary>
    /// http://de.wikipedia.org/wiki/%C3%84pfel
    /// </summary>
    public class Apfel : Pyrinae { }

    /// <summary>
    /// http://de.wikipedia.org/wiki/Birnen
    /// </summary>
    public class Birne : Pyrinae { }

    public static class Program
    {
        public static void Main()
        {
            Apfel apfel = new Apfel();
            apfel.Name = "Granny Smith";
            apfel.AnzahlKerne = 5;
            Birne birne = new Birne();
            birne.Name = "Helene";
            birne.AnzahlKerne = 3;
            List<Pyrinae> korb = new List<Pyrinae>(2);
            korb.Add(apfel);
            korb.Add(birne);
            korb.Sort();
            foreach (Pyrinae frucht in korb)
            {
                Console.WriteLine(frucht.Name);
            }
            Console.ReadLine();
        }
    }
}