基类与派生类之间的互相转换，使用指针的情况
源程序：
#include<iostream>
using namespace std;
class CBase
{
protected:
int n;
public:
CBase(int i):n(i){}
void Print()
{
cout<<"CBase:n="<<n<<endl;
}
};
class CDerived:public CBase
{
public:
int v;
CDerived(int i):CBase(i),v(2*i){}
void Func(){};
void Print()
{
cout<<"CDerived:n="<<n<<endl;
cout<<"CDerived:v="<<v<<endl;
}
};
int main()
{
CDerived objDerived(3);
CBase objBase(5);
CBase *pBase = &objDerived;
CDerived *pDerived;
pDerived = &objDerived;
cout<<"使用派生类指针调用函数"<<endl;
pDerived->Print();
pBase=pDerived;
cout<<"使用基类指针调用函数"<<endl;
pBase->Print();
//pBase->Func(); //错误，通过基类指针不能调用派生类函数
//pDerived=pBase; //错误，派生类指针=基类指针
pDerived=(CDerived*)pBase; //强制类型转换，派生类指针=基类指针
cout<<"使用派生类指针调用函数"<<endl;
pDerived->Print();
return 0;
}
运行结果：
