虛函數(shù)被類的構(gòu)造析構(gòu)函數(shù)和成員函數(shù)調(diào)用虛函數(shù)的執(zhí)行過程

2020-01-26 16:22:13

字體：大中小

供稿：網(wǎng)友

#include<iostream>

class base{
public:

    base()
    {
        std::cout<<std::endl;
        std::cout<<"base constructor"<<std::endl;
        func1();
        std::cout<<std::endl;
    }

    virtual ~base()
    {
        std::cout<<std::endl;
        std::cout<<"base distructor"<<std::endl;
        func1();
        std::cout<<std::endl;
    }
    virtual void func1()
    {
        std::cout<<"base virtural func1"<<std::endl;
    }

    void func2()
    {
        std::cout<<"base member func2"<<std::endl;
        func1();
        std::cout<<std::endl;
    }
};

class derived:public base{
public:
    derived()
    {
        std::cout<<std::endl;
        std::cout<<"derived constructor"<<std::endl;
        func1();
        std::cout<<std::endl;
    }

    virtual ~derived()
    {
        std::cout<<std::endl;
        std::cout<<"derived distructor"<<std::endl;
        func1();
        std::cout<<std::endl;
    }

    virtual void func1()
    {
        std::cout<<"derived virtual func1"<<std::endl;
    }

};

int main()
{
    base *point = new derived();
    point->func2();
    delete point;
    return 0;
}

會(huì)有這樣的輸出

即使func1是虛函數(shù)，在base類和derived的構(gòu)造函數(shù)和析構(gòu)函數(shù)里面，都是調(diào)用自己類里面的func1。