多重继承 virtual

最新推荐文章于 2024-12-02 11:18:38 发布

parngoo

最新推荐文章于 2024-12-02 11:18:38 发布

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分类专栏： PROGRAM 文章标签： string class function

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本文通过一个具体的C++示例，展示了如何使用虚拟继承来避免在多重继承中重复包含父类子对象的问题，包括成员数据和成员函数。通过示例代码详细解释了虚拟继承的工作原理。

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虚拟继承可以使继承自自己的class避免重复包含subobject of parent's parent,既包括member data,也包括member function.
如果不使用virtual继承，那在多重继承的时候就会有多份copy在对象中，那调用parnent member function时就不知道调用那一份copy

// multiBaseClassTest.cpp : Defines the entry point for the console application. // #include "stdafx.h" using namespace std; class Stuff { public: Stuff(string &name): _name(name) { cout << "Stuff::Stuff(string &name)" << endl; } ~Stuff(){ cout << "Stuff::~Stuff()" << endl; } string& get_name(void) { cout << "Stuff::get_name()" << endl; return _name; } string set_name(string &name) { cout << "Stuff::set_name()" << endl; _name = name; } private: string _name; }; class Car : virtual public Stuff { public: Car(string &name):Stuff(name) { cout << "Car::Car(string &name)" << endl; _tyre = "tyre4"; } ~Car() {cout << "Car::~Car()" << endl;} string get_special(void ){ cout << "Car::get_special()" << endl; return _tyre;} private: string _tyre; }; class Ship : virtual public Stuff { public: Ship(string &name):Stuff(name) {cout << "Ship::Ship(string &name)" << endl; _quant = "quant2"; } ~Ship(){cout << "Ship::~Ship()" << endl;} string get_special(void ){ cout << "Ship::get_special()" << endl; return _quant;} private: string _quant; }; class ShipCar : public Ship, public Car { public: ShipCar(string &name):Stuff(name), Ship(name), Car(name) {cout << "ShipCar::ShipCar(string &name)" << endl;} ~ShipCar(){cout << "ShipCar::~ShipCar()" << endl;} string get_special(void){ return Ship::get_special().append(Car::get_special()); } }; void Test1(void) { string name = "car1"; Car car1(name); car1.get_name(); } void Test2(void) { string name = "ship1"; Ship ship1(name); } void Test3(void) { string name = "shipcar1"; ShipCar shipcar1(name); shipcar1.get_name(); shipcar1.get_special(); } int _tmain(int argc, _TCHAR* argv[]) { Test1(); cout << endl; Test2(); cout << endl; Test3(); return 0; }