筆記一下
C++ class繼承有三種修飾詞 分別是private/protected/public
private subclass
外部會視super class中的public & protected members為private members
protected subclass
外部會視super class中的public & protected members為protected members
public subclass
會維持super class中的修飾詞 也就是外部會視public members仍是public members protected members仍是protected members