observer

网上找的，不是自己写的

放上链接

blog.csdn.net/lcl_data/article/details/9208561

observer.cpp

#include <iostream>

#include <vector>

#include <string>

using namespace std;

class Secretary;

// 看股票的同事类（观察对象，观察者）

class StockObserver

{

public:

StockObserver(string strName, Secretary* strSub)

{ name = strName; sub = strSub; }

void Update();

private:

string name;

Secretary* sub;

};

// 秘书类（主题对象，通知者）

class Secretary

{

public:

string action;

void Add(StockObserver ob) {

observers.push_back(ob);

} void Remove(int addIndex) {

if(addIndex >=0 && addIndex < observers.size()) observers.erase(observers.begin() + addIndex); }

void Notify() {

vector<StockObserver>::iterator it;

for (it=observers.begin(); it!=observers.end(); ++it)

{ (*it).Update(); }

}

private:

vector<StockObserver>observers;

};

void StockObserver::Update()

{

cout << name << " : " << sub->action << ", begin to work" << endl;

}

int main()

{

// 创建通知者

Secretary* p = new Secretary();

// 观察者

StockObserver* s1 = new StockObserver("Lazy", p);

StockObserver* s2 = new StockObserver("SnowFire", p);

// 加入通知队列

p->Add(*s1);

p->Add(*s2);

// 事件

p->action = "The boss is coming...";

// 通知

p->Notify();

// 动态删除

p->Remove(0);

p->Notify();

return 0;

}

编译:make observer