填空题

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; } };