23种设计模式C++实例之代理模式

代理的目的是一般是为了防止直接访问某一个类，提供一种类似授权的机制。

最典型的类中set和get方法实际上就是一种代理。

#include <iostream>using namespace std;/* * 代理模式:为其他对象提供一种代理，并以控制对这个对象的访问 * a类中b类，a类和b类中都实现协议类protocol * */class Shop{public:virtual ~Shop() {}virtual void sell() = 0;};class BookShop: public Shop {public:virtual void sell() {cout << "sell book" << endl;}};class NetShop: public Shop {public:NetShop() {m_shop = new BookShop();}virtual ~NetShop() {if ( m_shop != NULL ) {delete m_shop;m_shop = NULL;} }virtual void sell() {discount();m_shop->sell();}void discount() {cout << "discount" << endl;}private:Shop* m_shop;};int main() {NetShop* netShop = new NetShop;netShop->sell();delete netShop;return 0;}