四则运算及验证码

四则运算

 1 package 小学四则运算;
 2 
 3 import java.util.*;
 4 
 5 //预计用时1个小时,开始于4.45,结束与5.30.实际用时45分钟
 6 public class PrimaryOperation {
 7 
 8     public static void main(String[] args) {
 9         
10         for (int i = 0; i <30; i++) {
11             
12             int choice = (int)(Math.random()*5);
13             switch (choice) {
14             // +
15             case 0:
16                 doAdd(i+1);
17                 break;
18             // -
19             case 1:
20                 doReduce(i+1);
21                 break;
22             // *
23             case 2:
24                 doMul(i+1);
25                 break;
26             // /
27             case 3:
28                 doDivide(i+1);
29                 break;
30             }
31         }
32     }
33 //   /
34     private static void doDivide(int i) {
35         System.out.println("第"+i+"次为:");
36         
37         int one=(int)(Math.random()*1000);
38         int two=(int)(Math.random()*1000);
39         
40         System.out.println(one+"/"+two+"="+"

");
41     }
42 // *
43     private static void doMul(int i) {
44         System.out.println("第"+i+"次为:");
45         int one=(int)(Math.random()*1000);
46         int two=(int)(Math.random()*1000);
47         System.out.println(one+"*"+two+"="+"

");
48     }
49 // -
50     private static void doReduce(int i) {
51         System.out.println("第"+i+"次为:");
52         int one=(int)(Math.random()*1000);
53         int two=(int)(Math.random()*1000);
54         System.out.println(one+"-"+two+"="+"

");
55 
56     }
57 // +
58     private static void doAdd(int i) {
59         System.out.println("第"+i+"次为:");
60         int one=(int)(Math.random()*1000);
61         int two=(int)(Math.random()*1000);
62         System.out.println(one+"+"+two+"="+"

");
63 
64     }
65 
66 }

验证码

 1 package 课堂测试3;
 2 
 3 import java.util.Random;
 4 import java.awt.Container;
 5 import java.awt.Dimension;
 6 import java.awt.FlowLayout;
 7 
 8 import javax.swing.ImageIcon;//顶级容器即空白窗口     
 9 import javax.swing.JButton;
10 import javax.swing.JFrame;
11 import javax.swing.JLabel;
12 import javax.swing.JPanel;
13 import javax.swing.JPasswordField;
14 import javax.swing.JTextField;
15 
16 public class Test {
17 
18     public static void main(String[] args) {
19     Test t=new Test();
20     t.set();
21     
22     }
23 
24     private void set() {
25         JFrame f=new JFrame();
26         f.setTitle("验证码");//窗口标题
27         f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);//关闭
28         /*
29          * setDefaultCloseOperation()
30          * 设置默认的关闭窗口时的操作,取值为:
31          * DO_NOTHING_ON_CLOSE//小
32          * HIDE_ON_CLOSE
33          * DISPOSE_ON_CLOSE
34          * EXIT_ON_CLOSE
35          */
36         f.setExtendedState(JFrame.MAXIMIZED_VERT);//最大化
37         /*
38          * setExtendedState()
39          * 设置扩展状态,取值为:
40          * NORMAL//小
41          * ICONIFIED//不弹出(运行),小
42          * MAXIMIZED_HORIZ//小
43          * MAXIMIZED_VERT//小
44          * MAXIMIZED_BOTH//全屏
45          */
46         f.setSize(300,300);//窗口大小
47     
48         /*
49          * 设置图标图像
50          * 图标:javax.swing.ImageIcon
51          * 图像:javax.awt.Image
52          * 创建图标:ImageIcon tu=new ImageIcon("图标位置");
53          * 创建图像:Image image=new Image();
54          * 设置:setIconImage(image);
55          */
56         /*
57          * 添加标签
58          * JLabel yan=new JLabel("姓名");
59          */
60         Container con=f.getContentPane();
61         JPanel pan=new JPanel();
62         JLabel yan=new JLabel("验证码:");
63         pan.add(yan);
64         JTextField yanzhengma=new JTextField(10);
65         pan.add(yanzhengma);
66         
67         /*
68          * 随机字符,生成验证码
69          */
70         
71         String str = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789";
72         Random random = new Random();
73         StringBuffer yzm = new StringBuffer();
74  
75         for (int i = 0; i < 4; ++i) {
76             int number = random.nextInt(62);// [0,62)
77             yzm.append(str.charAt(number));
78         }
79         String s=yzm.toString();
80         JLabel ma=new JLabel(s);
81         pan.add(ma);
82         /*
83          * 按钮构造,类为JButten;
84          * 方法:
85          * JButton buttenOne=new JButton("确定");
86          */
87          JButton buttenOne=new JButton("确定");
88         pan.add(buttenOne);
89         
90         con.add(pan);
91         f.setVisible(true);
92         //窗口实现
93     }
94 }

在这两个小程序的编写中有很多方法的使用,以及新的Swing的各种方法

以后有的学了,

原文地址:https://www.cnblogs.com/msdog/p/9752448.html