下面这个题目选啥，关于c++虚指针的？？？

#include<iostream>
using namespace std;
class CBase
{
public:
	void func()
	{
		Print();
	}
	virtual void Print()
	{
		cout<<"CBase::Print"<<endl;
	}
};
class CDerived : public CBase
{
public:
	virtual void Print()
	{
		cout<<"CDerived::Print"<<endl;
	}
};

int main(void)
{
	CDerived c;
	CBase *p = &c;
	cout<<sizeof(*p)<<endl;
	getchar();
	return 0;
}
我想说，vs2010上运行了一下，sizeof(*p)的答案是不是4，可是答案给的是8，不理解？？