右边的类对象决定查看的虚函数表..左边的类型调用非函数表

class A

{

public:
virtual void F1()
{
cout<<"A1"<<endl;
}
void F2()
{
cout<<"A2"<<endl;
}

};

class B :public A

{

public:
void F1()
{
cout<<"B1"<<endl;
}
void F2()
{
cout<<"B2"<<endl;
}

};

void main(){

A *pa;
B *pb;
B TB;
A TA;

pa = &TB;//基类指针指向派生类对象
pa->F1();
pa->F2();

pb =(B *) &TA;//派生类指针指向基类对象            查对象的虚函数表,   指针的类型决定函数

pb->F1();
pb->F2();

}