class Subject {
public:
    virtual ~Subject() = default;
    virtual void request() = 0;
};

class RealSubject : public Subject {
public:
    void request() override {
        std::cout << "RealSubject: 处理请求。\n";
    }
};

class Proxy : public Subject {
private:
    RealSubject* real_subject_;
<pre class='brush:php;toolbar:false;'>void init_real_subject() {
    if (!real_subject_) {
        real_subject_ = new RealSubject();
    }
}

public: Proxy() : realsubject(nullptr) {}

~Proxy() override {
    delete real_subject_;
}

void request() override {
    init_real_subject(); // 懒加载
    std::cout << "Proxy: 在转发请求前记录日志。\n";
    real_subject_->request();
}

};

第一款时尚产品在线设计平台，服装设计系统

int main() {
    Proxy proxy;
    proxy.request();
<pre class='brush:php;toolbar:false;'>return 0;

}