using System.Text;using System.Collections.Generic;using System.Linq;using System;namespace 观察者{    public interface IServer    {  void Notice( IClient C);    }    public interface IClient    {  void Show();    } public class Person : IClient {  public Person( IServer S )  {           S.Notice(this);  }  public void Show()  {   Console.WriteLine("主人被惊醒了");  } } public class Mouses : IClient {  public Nouses( IServer C )  {   C.Notice( this );  }  public void Show()  {   Console.WriteLine("老鼠被吓跑了");  } }    public class Tom : IServer    {  ArrayList al =new ArrayList();  public void Notice(IClient C)  {   al.Add( C );  }  public void Runs()  {   Console.WriteLine("猫叫了");   foreach (IClient item in al)   {    item.Show();   }  }    }     class Test {  static void Main(string[] args)  {   Tom t=new Tom();   Person p=new Person(t);   Mouses m =new Mouses(t);   t.Runs();  } }}