模仿mem_fun函数的功能

最新推荐文章于 2021-12-14 09:31:54 发布

原创最新推荐文章于 2021-12-14 09:31:54 发布 · 483 阅读

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#fun #function #each #include #delete

本文通过一个C++程序实例介绍了如何使用静态成员变量跟踪类实例的数量，并展示了如何利用模板函数对对象集合进行操作。该程序创建了一个包含多个Widget实例的容器，并使用模板函数遍历这些实例以调用其成员方法。

#include <iostream> #include <algorithm> #include <vector> #include <string> using namespace std; class Widget { static int counter; public: Widget() { counter++; cout<<"my id is:"<<counter<<endl; cout<<"this is one day i come to this world"<<endl; } virtual ~Widget() { counter--; cout<<"there 's on day i will leave from this world"<<endl; } void ShowInfor() { cout<<"my id is:"<<counter<<endl; } void Running() { cout<<"i can running fast enough to reach the moon"<<endl; } }; //typedef void (Widget::*fun)() ; int Widget::counter=0; //template<class Function> class function { private: typedef void (Widget::*Fun)(); Fun fun; public: function(Fun fun) { this->fun=fun; } void operator()(Widget *wid) { (wid->*fun)(); } }; void Destroy(Widget *wid) { delete wid; } int main() { vector<Widget*> widgets; for(int i=0; i<10; i++) { widgets.push_back(new Widget()); } for_each(widgets.begin(),widgets.end(),function(&Widget::ShowInfor)); for_each(widgets.begin(),widgets.end(),function(&Widget::Running)); return 0; }