C++学习（1）--基类、派生类的对象空间

#include<iostream>#include<stdio.h>using namespace std;//基类class CMyBase{    int x;    int y;public:    int SetX(int nValue){return x=nValue;}    int GetX(){return x;}    int SetY(int nValue){return y=nValue;}    int GetY(){return y;}    void print(){cout<<"in the base class : x = "<<x<<endl;}    void printY(){cout<<"in the base class : y = "<<y<<endl;}};//派生类/**公有派生类*///基类共有成员相当于派生类的公有成员//基类私有成员派生类无论如何都不能访问//基类保护成员相当于派生类的保护成员/**私有派生*///基类共有成员相当于派生类的私有成员//基类私有成员派生类无论如何都不能访问//基类保护成员相当于派生类的私有成员class CMyDerive:public CMyBase{    int x;    //派生类中的成员变量隐藏基类的成员变量public:    int SetX(int nValue){return x=nValue;}    int GetX(){return x;}    //基类中的成员函数被重新定义    void print(){cout<<"in the derive class : x = "<<x<<endl;}    void printY(){cout<<"in the derive class : y = "<<GetY()<<endl;}};int main(){    CMyBase obj1;    obj1.SetX(1000);    obj1.print();//1000    cout<<"in main function, in the base    class : x = "<<obj1.GetX()<<endl;//1000    cout<<endl;    CMyDerive obj2;    obj2.SetX(300);//初始化派生类私有成员x    obj2.print();//300    obj2.SetY(123456);    obj2.printY();//访问派生类私有成员    obj2.CMyBase::printY();//访问基类公共成员    /*    **为了解决二义性，通过在所访问的成员名前加上所属类域来强制访问基类的成员    **    */    obj2.CMyBase::print();//4273296  由于基类中的x没有初始化，所以得到的是个不确定的值     cout<<"in main function, in the derived class : x = "<<obj2.GetX()<<endl;//300    cout<<"in main function, in the base    class : x = "<<obj2.CMyBase::GetX()<<endl;//4273296    obj2.CMyBase::SetX(200);//初始化    obj2.print();//300    obj2.CMyBase::print();//200    cout<<"in main function, in the derived class : x = "<<obj2.GetX()<<endl;//300    cout<<"in main function, in the base    class : x = "<<obj2.CMyBase::GetX()<<endl;//200    return 0;}