（6）代理模式

指具有与代理元具有相同的接口的类，客户端必须通过代理与被代理的目标类交互，而代理一般在交互的过程中（交互前后），进行某些特别的处理。

#include<iostream>using namespace std;class subject {public:virtual void sell() = 0;};class shop :public subject {public :void sell() override {cout << "商店卖书" << endl;}};class taobao :public subject {public:void sell() override{shop *su = new shop;su->sell();}};void main() {subject *s = new taobao;s->sell();delete s;system("pause");}