程序设计: 猫大叫一声，所有的老鼠都开始逃跑，主人被惊醒。(C#语言)
要求：
<1>.构造出Cat、Mouse、Master三个类，并能使程序运行
<2>从Mouse和Master中提取抽象
<3>联动效应，只要执行Cat.Cryed()就可以使老鼠逃跑，主人惊醒。
using System;
using System.Collections;
using System.Collections.Generic ;
namespace gtkTest
{
public class ObserverClass
{
public ObserverClass ()
{
}
public static void ObserverFun ()
{
Cat cat = new Cat();
Mouse mouse1 = new Mouse("mouse1", cat);
Mouse mouse2 = new Mouse("mouse2", cat);
Master master = new Master(cat);
cat.Cry();
}
public interface Observer
{
void Response(); //观察者的响应，如是老鼠见到猫的反映
}
public interface Subject
{
void AimAt(Observer obs); //针对哪些观察者，这里指猫的要扑捉的对象---老鼠
}
public class Mouse : Observer
{
private string name;
public Mouse(string name, Subject subj)
{
this.name = name;
subj.AimAt(this);
}
public void Response()
{
Console.WriteLine(name + " attempt to escape!");
}
}
public class Master : Observer
{
public Master(Subject subj)
{
subj.AimAt(this);
}
public void Response()
{
Console.WriteLine("Host waken!");
}
}
public class Cat : Subject
{
private ArrayList observers;
public Cat()
{
this.observers = new ArrayList();
}
public void AimAt(Observer obs)
{
this.observers.Add(obs);
}
public void Cry()
{
Console.WriteLine("Cat cryed!");
foreach (Observer obs in this.observers)
{
obs.Response();
}
}
}
}
}
//2
using System;
namespace gtkTest
{
public class ObserverDeleClass
{
public ObserverDeleClass ()
{
}
public static void ObserverDeleFun ()
{
Cat cat = new Cat();
Mouse mouse1 = new Mouse("ObserverDelemouse1", cat);
Mouse mouse2 = new Mouse("ObserverDelemouse2", cat);
Master master = new Master(cat);
cat.Cry();
}
//---------------------------------------------------------------------------------------------
//设计方法二: 使用event -- delegate设计..
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("ObserverDelecat 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("ObserverDelehost waken");
}
}
}
}
//3
gtkTest.ObserverDeleClass.ObserverDeleFun();
gtkTest.ObserverClass.ObserverFun ();
参考： https://blog.csdn.net/hunterxray/article/details/1532674
一列数的规则如下: 1、1、2、3、5、8、13、21、34...... 求第30位数是多少， 用递归算法实现
public class MainClass
{
public static void Main()
{
Console.WriteLine(Foo(30));
}
public static int Foo(int i)
{
if (i <= 0)
return 0;
else if(i > 0 && i <= 2)
return 1;
else return Foo(i -1) + Foo(i - 2);
}
}
参考：https://blog.csdn.net/zhangzuqing/article/details/20208385
原文：https://www.cnblogs.com/2186009311CFF/p/9210893.html