18.3.3 第四章 4.1继承（1）

package demo;

import java.util.ArrayList;

public class Database {
private ArrayList<CD> listCD=new ArrayList<CD>();
private ArrayList<DVD> listDVD=new ArrayList<DVD>();
private void add(CD cd) {
listCD.add(cd);
}

private void add(DVD dvd) {
listDVD.add(dvd);
}

public void list() {
for (CD cd:listCD) {
cd.print();
}
for(DVD dvd:listDVD) {
dvd.print();
}
}

public static void main(String[] args) {
// TODO Auto-generated method stub
Database db=new Database();
db.add(new CD("abc","abc",4,60,"..."));
db.add(new CD("def","def",4,60,"..."));
db.add(new DVD("xxx","aaa",60, "..."));
db.list();
}

}

package demo;

public class DVD {
private String title;
private String director;
private int playingTime;
private boolean gotIt=false;
private String comment;
public static void main(String[] args) {
// TODO Auto-generated method stub

}
public DVD(String title, String director, int playingTime, String comment) {
super();
this.title = title;
this.director = director;
this.playingTime = playingTime;
this.gotIt = gotIt;
this.comment = comment;
}
public void print() {
// TODO Auto-generated method stub
System.out.println("DVD"+":"+title+":"+director);

}

}

package demo;

public class CD {
private String title;
private String artist;
private int numofTracks;
private int playingTime;
private boolean gotIt=false;
private String comment;

public CD(String title, String artist, int numofTracks, int playingTime, String comment) {
//		super();
this.title = title;
this.artist = artist;
this.numofTracks = numofTracks;
this.playingTime = playingTime;
this.gotIt = gotIt;
this.comment = comment;
}

public static void main(String[] args) {
// TODO Auto-generated method stub

}

public void print() {
// TODO Auto-generated method stub
System.out.println("CD"+":"+title+":"+artist);

}

}