Exempel - Human

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Human {
    class Program {
        static void Main(string[] args) {

            Forum flashback = new Forum();
            flashback.members.Add(new Spanish());
            flashback.members.Add(new Swedish());
            flashback.members.Add(new English());
            Console.WriteLine("Humans created: " + Human.objectsCreated);
            flashback.MakePeopleTalk();
            Console.ReadKey(true);
        }
    }
    public class Forum {
        public Forum() {
            members = new List<Human>();
        }
        public void MakePeopleTalk() {
            foreach(Human h in members) {
                h.Talk();
            }
        }
        public List<Human> members;
    }
    public interface INationalSong {
        string getNationalSongTitle();
    }
    public abstract class Human {
        public static int objectsCreated { get; private set; } = 0;
        public Human() { objectsCreated++; }
        public virtual void Talk() {
            Console.WriteLine("The human says: hi mi estas viro");
        }
        public abstract void sayHello();
    }
    public class Swedish : Human, INationalSong {
        public Swedish() { }
        public void sing() {
            Console.WriteLine("Nä, här i sverige sjunger man inte");
        }
        public override void Talk() {
            Console.WriteLine("The swede says: flashback forum är ju där man får lite vett om världen");
        }
        public override void sayHello() {
            Console.WriteLine("Tjänare Bengt");
        }
        string INationalSong.getNationalSongTitle() {
            return "Du gamla du fria";
        }
    }
    public class English : Human {
        public English() { }
        public override void sayHello() {
            Console.WriteLine("Good evening, sir");
        }
        public override void Talk() {
            Console.WriteLine("The englishman says: it's tea o'clock *slurp slurp*");
        }
    }
    public class Spanish : Human {
        public Spanish() { }
        public override void sayHello() {
            Console.WriteLine("Ni hao");
        }
        public override void Talk() {
            Console.WriteLine("The spaniard says: hola hola maldito burrito");
        }
    }

}