bool gettop(e& x) const ∥取栈顶 bool Is Empty const return top== nUll; void makeempty(: 清空栈的内容 friend ostream& operator <<(ostream& os LinkedStack<E> &s); /出栈元素的重载操作<<17 bool getTop(E& x) const; //取栈顶 bool IsEmpty() const { return top == NULL; } void makeEmpty(); //清空栈的内容 friend ostream& operator << (ostream& os, LinkedStack<E> & s) ; //输出栈元素的重载操作 << };