重症肺炎常合并_______、________、________、_______、________、_______。

请将下列类定义补充完整。
class Base(public:void fun()cout＜＜"Base::fun"＜＜end1;;
class Derived:public Base

public:
void fun()

______//显式调用基类的fun函数
cout＜＜"Derived::fun"＜＜end1;

;