改进1: void tune( nstrument&i)/向上转型 class Instrument payO-际{ void play( i cout<< instrument play?< <endl; void maino Wind flute Stringed violin class Wind Percussion drum, tune(flute) 希望 void playo tune(violin) i cout<<Wind play<<endl;) tune(drum)改进1： void tune(Instrument& i) //向上转型 { } i.play(); …… void main() { } Wind flute; Stringed violin; Percussion drum; tune(drum); tune (flute); tune (violin); class Wind { }; …… void play() { cout<<“Wind play”<<endl; } 希望 class Instrument { }; …… void play() { cout<<“instrument play”<<endl; } 实际