[C++知识库] 观察者模式

开发: C++知识库 Java知识库 JavaScript Python PHP知识库人工智能区块链大数据移动开发嵌入式开发工具数据结构与算法开发测试游戏开发网络协议系统运维
教程: HTML教程 CSS教程 JavaScript教程 Go语言教程 JQuery教程 VUE教程 VUE3教程 Bootstrap教程 SQL数据库教程 C语言教程 C++教程 Java教程 Python教程 Python3教程 C#教程
数码: 电脑笔记本显卡显示器固态硬盘硬盘耳机手机 iphone vivo oppo 小米华为单反装机图拉丁

-> C++知识库 -> 观察者模式 -> 正文阅读

[C++知识库]观察者模式

代码实现

#include<iostream>
#include<string>
using namespace std;
#include<list>
class Observer
{
public:
	virtual void Update() = 0;
};

class Subject
{
public:
	void notify()
	{
		for (auto obs = observers.begin(); obs != observers.end(); obs++)
		{
			(*obs)->Update();
		}
	}
	void addobj(Observer*ob)
	{
		observers.push_back(ob);
	}
	void removeobj(Observer *ob)
	{
		observers.remove(ob);
	}

private:
	list<Observer*>observers;
};

class ConSubject :public Subject
{
public:
	void setState(int sta)
	{
		mState = sta;
	}
	int getState()
	{
		return mState;
	}

private:
	int mState;
};

class ConObserver :public Observer
{
public:
	ConObserver(ConSubject *consub, string name ,string thing1,string thing2)
	{
		mSub = consub;
		mThing1 = thing1;
		mThing2 = thing2;

		mName = name;
	}

	virtual void Update()
	{
		int state = mSub->getState();

		if (state == 1)
		{
			cout << mName << "  " << mThing1 << endl;
		}
		else
		{
			cout << mName << "  " << mThing2 << endl;
		}
	}


private:
	ConSubject *mSub;

	string mThing1;
	string mThing2;
	
	string mName;
	
};

测试

#include"Observer.h"
int main()
{
	ConSubject *cs = new ConSubject();
	cs->setState(1);

	Observer *co1 = new ConObserver(cs, "xianming", "have fun", "study");

	Observer *co2 = new ConObserver(cs, "xiaohong", "eat", "drink");

	cs->addobj(co1);
	cs->addobj(co2);
	cs->notify();

	cs->setState(2);
	cs->notify();

	system("pause");

	delete cs;
	delete co1;
	delete co2;
	return 0;
}