Button->action_ can not be used as a function...

bitzilla

代码是根据《C++ common knowledge》上“command模式和好莱坞法则”这一节写的。
但是编译的时候有错。
其中，1. Button类的action_,报错－cannot be used as a function;
2. main()函数中的b->setAction(song);包错－no matching function for setAction（auto_ptr<layMusic>&;
应该怎么解决这两个问题呢？

#include <iostream> using namespace std; class Action {//command public: &nbsp;&nbsp;&nbsp;&nbsp;virtual ~Action(){}; &nbsp;&nbsp;&nbsp;&nbsp;virtual void operator() () = 0; &nbsp;&nbsp;&nbsp;&nbsp;virtual Action *clone() const = 0;//prototype }; class Button { public: &nbsp;&nbsp;&nbsp;&nbsp;Button(const string &label) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;:label_(label), action_(0) { } &nbsp;&nbsp;&nbsp;&nbsp;void setAction(const Action *newAction); &nbsp;&nbsp;&nbsp;&nbsp;void onClick() const; private: &nbsp;&nbsp;&nbsp;&nbsp;string label_; &nbsp;&nbsp;&nbsp;&nbsp;Action *action_;//command }; void Button::setAction(const Action *newAction) { &nbsp;&nbsp;&nbsp;&nbsp;Action *tmp = newAction->clone(); &nbsp;&nbsp;&nbsp;&nbsp;delete action_; &nbsp;&nbsp;&nbsp;&nbsp;action_ = tmp; } void Button::onClick() const { &nbsp;&nbsp;&nbsp;&nbsp;if(action_) &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;action_(); } class PlayMusic:public Action { public: &nbsp;&nbsp;&nbsp;&nbsplayMusic(const string &songfile):song_(songfile){} &nbsp;&nbsp;&nbsp;&nbsp;void operator()(); &nbsp;&nbsp;&nbsp;&nbsplayMusic *clone() const; private: &nbsp;&nbsp;&nbsp;&nbsp;string song_; }; void PlayMusic::operator()() //播放音乐动作的执行代码 { &nbsp;&nbsp;&nbsp;&nbsp;cout<<"I am playing music, song name is "<<song_<<endl; } PlayMusic *PlayMusic::clone() const { &nbsp;&nbsp;&nbsp;&nbsp;return new PlayMusic(song_); } int main() { &nbsp;&nbsp;&nbsp;&nbsp;Button *b = new Button("Anoko no namaewa"); &nbsp;&nbsp;&nbsp;&nbsp;auto_ptr<PlayMusic> &nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;song(new PlayMusic("Anokononamaewa.mp3")); &nbsp;&nbsp;&nbsp;&nbsp;b->setAction(song); }