C#经典机试题(猫叫)

public delegate void SubEventHandler();

public abstract class Subject {
public event SubEventHandler SubEvent;
protected void FireAway() {
if (this.SubEvent != null)
this.SubEvent();
}
}
public class Cat : Subject {
public void Cry() {
Console.WriteLine("cat cryed.");
this.FireAway();
}
}
public abstract class Observer {
public Observer(Subject sub) {
sub.SubEvent += new SubEventHandler(Response);
}
public abstract void Response();
}
public class Mouse : Observer {
private string name;
public Mouse(string name, Subject sub) : base(sub) {
this.name = name;
}
public override void Response() {
Console.WriteLine(name + " attempt to escape!");
}
}
public class Master : Observer {
public Master(Subject sub) : base(sub){
}
public override void Response() {
Console.WriteLine("host waken");
}
}
class Class1 {
static void Main(string[] args) {
Cat cat = new Cat();
Mouse mouse1 = new Mouse("mouse1", cat);
Mouse mouse2 = new Mouse("mouse2", cat);
Master master = new Master(cat); cat.Cry();
}
}