继承基类派生类,虚函数小结

基类TableTennisPlayer  派生类RatedPlayer

1.       基类指针可以在不进行显示类型转换的情况下指向派生类对象;基类引用可以在不进行显示类型转换的情况下引用派生类对象.

RatedPlayer palyer(1000,”Mallory”,true)  

TableTennisPlayer &rt = palyer;

TableTennisPlayer *pt = palyer;

2.       不可以将基类对象和地址赋给派生类引用和指针

TableTennisPlayer palyer(1000,“Betsy”);

RatedPlayer&rt = palyer;  ///NOT ALLOWED

RatedPlayer*pt = palyer;  ///NOT ALLOWED

3.       如果没有使用virtual,将根据引用类型或指针类型选择方法,如果使用了virtual,将根据引用或指针指向的对象来选择方法.

class Brass

{

private:

       string m_name;

       intm_age;

public:;

    Brass(conststring name,int age):m_name(name),m_age(age){};

       virtual void study(){cout<<"jackis studying C++"<<endl;}

       voidlove(){cout<<"Brass love"<<endl;}

};

class BrassPluse:publicBrass

{

private:

       string m_company;

public:

       BrassPluse(conststring &name,int age,const string &company):Brass(name,age),m_company(company){};

       virtual void study(){cout<<"jackis studying C++ in Tencent "<<endl;}

       voidlove(){cout<<"BrassPluse love"<<endl;}

};

void main()

{

       Brass dom("jack",24);

       BrassPluse doc("jack",24,"Tencent");

       Brass & rt =dom;

       Brass & rc =doc;

///定义virtual

       rt.study();

       rc.study();

       ///没有定义virtual

       rt.love();

       rc.love();

       system("pause");

}