都四次上课练习

package 课后四讲;
 2 
 3 import javax.swing.JOptionPane;
 4 
 5 class Example
 6 {
 7     static int value=0;
 8     public Example()
 9     {
10         value++;
11         
12     }
13 }
14 public class Ckleigeshu {
15 
16     public static void main(String[] args) {
17         Example section1=new Example();
18         Example section2=new Example();
19         Example section3=new Example();
20         String output="你已经创建了"+Example.value+"个对象";
21         JOptionPane.showMessageDialog(null, output,
22                     "结果如下：",
23                     JOptionPane.INFORMATION_MESSAGE );
24 
25     }
26 
27 }