c++虛函數重寫的權限問題
阿新 • • 發佈:2017-11-06
spa static mes ptr cast str iostream 調用 函數
cbase.h:
#ifndef CBASE_H
#define CBASE_H
#include<iostream>
using std::cout;
using std::endl;
class CBase{
public:
virtual void show();
};
#endif // CBASE_H
cbase.cpp:
#include"cbase.h"
void CBase::show()
{
cout<<"CBase"<<endl;
}
cderived.h:
#ifndef CDERIVED_H
#define CDERIVED_H
#include"cbase.h"
class CDerived:public CBase{
private:
void show() override;
};
#endif // CDERIVED_H
cderived.cpp:
#include"cderived.h"
void CDerived::show()
{
cout<<"CDerived"<<endl;
}
main.cpp:
#include <iostream>
#include"cderived.h"
using namespace std;
int main()
{
CBase* pBase=new CDerived;
pBase->show();
dynamic_cast<CDerived*>(pBase)->show();
delete pBase;
CDerived* pDerived=new CDerived;
pDerived->show();
static_cast<CBase*>(pDerived)->show();
delete pDerived;
return 0
}
程序運行會報錯:dynamic_cast<CDerived*>(pBase)->show();pDerived->show();
說是私有的不可調用
可見編譯器只看到了他所看到的,要從編譯器的角度看問題。只是把指針是什類型就是什麽類型。理解(*(p->vptr)[n])(p,...)
c++虛函數重寫的權限問題