12

1 public class L1106 {
 2 
 3     public static void main(String[] args) {
 4         // TODO Auto-generated method stub
 5         TestDemo circle1 = new TestDemo();
 6         double area=circle1.getArea();
 7         System.out.println(area);
 8         TestDemo circle2=new TestDemo(10);
 9         System.out.println(circle2.getArea());
10         System.out.println(circle1.getPerimeter());
11         System.out.println(circle2.getPerimeter());
12         double ridius=10;
13         double areaCircle=Math.PI*ridius*ridius;
14         System.out.println(areaCircle);
15         circle2.setRadius(5);
16         System.out.println(circle2.getArea());
17     }
18 
19 }

 1 public class TestDemo {
 2 
 3 private double radius;
 4     
 5     public TestDemo(double radius) {
 6         this.radius = radius;
 7     }
 8     public TestDemo() {
 9         this.radius = 1.0;
10     }
11     public double getArea() {
12         return Math.PI * radius * radius;
13     }
14     public double getPerimeter() {
15         return 2 * Math.PI * radius;
16     }
17     public void setRadius(double newRadius) {
18         this.radius = newRadius;
19     }
20 }

 1 package cn.TV;
 2 import java.util.Scanner;
 3 public class L {
 4     public int channel = 1;
 5     public int volume = 50;
 6     public boolean power = false;
 7     
 8     public void powerOn() {
 9         power = true;
10         System.out.println("欢迎使用LLTV,电视机已启动！");
11     }
12     public void powerOff() {
13         power = false;
14         System.out.println("Loading...");
15         System.out.println("**关机**");
16     }
17     public int getChannel() {
18         return channel;
19     }
20     public void setChannel(int channel) {
21         if(power) {
22             if(channel >= 1 && channel <= 100) {
23                 this.channel = channel;
24                 System.out.println("正在收看LLTV：" + channel );
25             }else {
26                 System.out.println("您并未购买此频道信号！");
27             }
28         }else {
29             System.out.println("请检查您的电视信号接收线是否正常！");
30         }
31     }
32     public void channelUp() {
33         if(power  && channel < 100)
34             channel++;
35         else System.out.println("+++无信号+++");
36     }
37     public void channelDown() {
38         if(power  && channel > 1)
39             channel--;
40         else System.out.println("---无信号---");
41     }
42     public void volumeUp() {
43         if(power && volume < 100) {
44             volume++;
45             System.out.println("当前音量为：" + volume + "%！");
46         }else System.out.println("音量已达最大值");
47     }
48     public void volumeDown() {
49         if(power && volume > 0) {
50             volume--;
51             if(volume == 0)
52                 System.out.println("电视机已静音！");
53         }
54             
55     }
56     public static void main(String[] args) {
57         // TODO Auto-generated method stub
58         Scanner input = new Scanner(System.in);
59         L lltv = new L();
60         lltv.powerOn();
61         System.out.print("手动输入频道序号：");
62         int temp = Integer.valueOf(input.nextLine());;
63         lltv.setChannel(temp);
64         lltv.getChannel();
65         lltv.volumeUp();
66         lltv.volumeDown();
67     }
68 }