青青草这里只有精品,av在线播放观看,国产成人亚洲一区二区三区

when upcasting .....

// codes start
2

class base{//a base class
3

// constructor
5

public base(){
6

System.out.println("base class construct");
7

}
8

// perform
9

public void perform(){
10

System.out.println("base class perform");
11

}
12

// destructor
13

public void finalize(){
14

System.out.println("base class destruct");
15

}
16

}
17

class subbase extends base{// derive from base
20

// constructor
22

public subbase(){
23

System.out.println("sub class construct");
24

}
25

// perform
26

public void perform(){
27

System.out.println("sub class perform");
28

}
29

// destructor
30

public void finalize(){
31

System.out.println("sub class destruct");
32

}
33

}
34

public class casting{// test casting class
36

// constructor
37

public casting(){
38

System.out.println("begin casting test");
39

}
40

public static void main(String args[]){
42

base father = new base();
43

subbase son = new subbase();
44

father.perform();
46

son.perform();
47

father = (base)son; // <1>
49

father.perform();
50

son = (subbase)father; // <2>
52

son.perform();
53

father = (base)((subbase)father); // <3>
55

father.perform();
56

}
57

}
58

// codes end
60

Today ,when i go for a interview ,the project manager asked me this question !
Acturally ,It's just relate to the knowledge of reference && object !
Be carefull ,Nothing !

posted on 2008-05-25 19:40 devliu 閱讀(109) 評論(0) 編輯收藏

新用戶注冊刷新評論列表


只有注冊用戶登錄后才能發(fā)表評論。




網(wǎng)站導(dǎo)航: 博客園 IT新聞 Chat2DB C++博客博問管理

Love Java,Love China!

when upcasting .....

導(dǎo)航

統(tǒng)計

常用鏈接

留言簿(1)

隨筆檔案

搜索

最新評論