class Wind: public Instrument public vitual void play)∥ virtual可省略 i cout<< wind play <<endl; class Percussion public Instrument publIc virtual void play/ virtual可省略 i cout<< percussion play?<<endlclass Wind:public Instrument { }; public: vitual void play() //virtual可省略 { cout<<“wind play”<<endl; } class Percussion:public Instrument { }; public: virtual void play //virtual可省略 { cout<<“percunssion play”<<endl; }