C++子类指针和基类指针的转化

DarkSE

#include <iostream>
using namespace std;
class Base
{};
class Base1:public Base
{};
class Base2:public Base
{};
class Derived:public Base1,public Base2
{};
int main()
{
        Base *bptr;
        Derived *dptr;
        dptr = ( Derived * )( Base1 * )bptr;//dptr = ( Derived * )bptr;
}

不清楚到底dptr = ( Derived * )( Base1 * )bptr;为什么是两个指针( Derived * )( Base1 * )，而不能是( Derived * )

DAY

是不是向下转型啊！！

DarkSE

DAY 发表于 2016-7-6 14:56
是不是向下转型啊！！

就是基类转向指针的话为什么必须按照逐级转化呢