Date4_ex.java *

 

Date4_ex.java                                                              2012-7-229:35

 

1publicclassDate4

2{

3     privateintyear,month,day;       //实例变量,私有

4     staticintcount=0;              //类变量

5     publicDate4(int y,int m,int d)

6     {

7         year=y;

8         month=((m>=1)&(m<=12))?m:1;

9         day=((d>=1)&(d<=31))?d:1;

10         count++;

11     }

12     publicstaticvoidprint_count()  //类方法,只能访问类变量

13     {

14         System.out.println("count="+count+"    ");

15     }

16     publicvoidprint()                //实例方法,可以访问类变量和实例变量

17     {

18         print_count();                 //调用类方法;

19         System.out.println("dateis"+year+"-"+month+"-"+day);

20     }

21     publicvoidfinalize()             //折构方法

22     {

23         count--;

24         System.out.println("count="+count+"    ");

25     }

26}

27

28classDate4_ex

29{

30     publicstaticvoidmain(Stringargs[])

31     {

32         Date4a=newDate4(2012,7,21);

33         System.out.println("----------a.print_count();---------");

34         a.print_count();

35         System.out.println("----------a.print();---------------");

36         a.print();

37         Date4b=newDate4(2012,12,30);

38         System.out.println("----------b.print();---------------");

39         b.print();

40         System.out.println("----------a.finalize();------------");

41         a.finalize();

42         System.out.println("----------b.print_count();---------");

43         Date4.print_count();

44     }

45}

46

输出结果:

E:\src\chapter3>java Date4_ex

----------a.print_count();---------

count=1

----------a.print();---------------

count=1

date is 2012-7-21

----------b.print();---------------

count=2

date is 2012-12-30

----------a.finalize();------------

count=1

----------b.print_count();---------

count=1

 

 

 

 

 

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