Java编程测试_类的使用

 1 package test;
 2 
 3 class A
 4 {
 5     private static int i;           // Static, Private Attribute
 6     private static int j;           // Static, Private Attribute
 7     private static int cnt = 0;        // Statistic the number of the object
 8     void set(int a , int b)         // Set the value by the function in class
 9     {                                   // The security can be guaranteed    
10         i = a;
11         j = b;
12     }
13     
14     public A(int a , int b)     // Construction Method
15     {
16         System.out.printf("The function has been called!\n");
17         i = a;
18         j = b;
19         cnt++;
20     }
21     
22     public static int Cnt()     //Get the number of the object in this class
23     {                            //It should can be static because we can 
24         return cnt;                //A.Cnt
25     }
26     
27     public void show()         // A Show Method in the class
28     {
29         System.out.printf("The value in this object: i=%d,j=%d\n",i,j);
30     }
31     
32     
33 }
34 
35 
36 ///////////Extends/////////////////////
37 class Human
38 {
39     public String name = "Mike";
40     public int age = 22;
41     }
42 
43 class Student extends Human
44 {
45     public double score = 90;
46     }
47 
48 class Graduate extends Student
49 {
50     public String tutor = "Jay";
51     }
52 /*************Extends**********************/
53 
54 
55 public class TestMemo {
56     
57     static int add(int a ,int b)                // The reentry of a function
58     {
59         return (a+b);
60     }
61     
62     static int add(int a ,int b , int c)        // The reentry of a function
63     {
64         return (a+b+c);
65     }
66 
67     static double add(double a ,double b)        // The reentry of a function
68     {
69         return a+b;
70     }
71     public static void main(String[] args)        // The reentry of a function
72     {
73         A aa = new A(66,88);
74 //        aa.i = 100;
75 //        aa.j = 20;
76         //aa.set(50, 67);
77         aa.show();
78         System.out.printf("Two int value be plused:%d\n",add(2,8));
79         System.out.printf("Three int value be plused:%d\n",add(1,2,3));
80         System.out.printf("Two float value be plused:%f\n",add(1.9,2.0));
81         A bb = new A(12,10);              //change the value in the class by another object
82         aa.show();                        // because of the static attribute
83         System.out.printf("The vaule count in A class: %d\n",A.Cnt());
84         Graduate stu = new Graduate();
85         System.out.printf("Test of EXTENDS: %s's tutor is %s\n",stu.name,stu.tutor);
86         System.out.printf("Test of EXTENDS: %s's age is %d\n",stu.name,stu.age);
87     }
88 }