就算改成private都可以，這個老師用的指針p不是Circle類的指針，而是int指針，所以不受訪問限定符的限定。

你可以用下面的代碼來看，p1是Circle類的指針，p2是int指針。

class?Circle?:?public?Shape{

public:
????Circle(int?radius);
????~Circle();

private:
????int?m_iR;
};

int?main()?{
????Circle?circle(200);
????cout?<<?"sizeof(circle)?=?"?<<?sizeof(circle)?<<?endl;

????//?Circle指針，無法訪問
????Circle?*p1?=?&circle;
????p1->m_iR;

????//?int指針，不受private限定符限制
????int?*p2?=?(int?*)&circle;

????cout?<<?"p2?=?"?<<?p2?<<?endl;
????cout?<<?"(unsigned?int)(*q)?=?"?<<?(unsigned?int)(*p2)?<<?endl;
}