ch9ex7.java

JAVA程序设计 丁岳伟 彭敦陆编 高等教育出版社 第7---11章程序

abstract class Instrument{
	int i;
	public abstract void play();
	public String what(){
		return "Instrument";
	}
  	public abstract void adjust();
}
class Wind extends Instrument{
	public void play(){
		System.out.println("Wind.play()");
	}
 	public String what(){return "Wind";}
  	public void adjust(){}
}
class Percussion extends Instrument{
	public void play(){
		System.out.println("Percussion.play()");
  	}
  	public String what(){return "Percussion";}
  	public void adjust(){}
}
class Stringed extends Instrument{
	public void play(){
		System.out.println("Stringed.play()");
	}
  	public String what(){return "Stringed";}
  	public void adjust(){}
}
class Brass extends Wind{
	public void play(){
		System.out.println("Brass.play()");
	}
  	public void adjust(){
  		System.out.println("Brass.adjust()");
  	}
}
class Woodwind extends Wind{
	public void play(){
		System.out.println("Woodwind.play()");
	}
  	public String what(){return "Woodwind";}
}
public class ch9ex7{
	static void tune(Instrument i){
    	i.play();
	}
	static void tuneAll(Instrument e[]){
    	for(int i=0;i<e.length;i++)
      		tune(e[i]);
      	}
  	public static void main(String[]args){
    	Instrument orchestra[]=new Instrument[5];
    	int i=0;
    	orchestra[i++]=new Wind();
    	orchestra[i++]=new Percussion();
    	orchestra[i++]=new Stringed();
    	orchestra[i++]=new Brass();
    	orchestra[i++]=new Woodwind();
    	tuneAll(orchestra);
  	}
}