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[Java教程]第九次作业

1package kk;public class circle {  private double radius;  // 构造方法,有参构造  public circle(double radius) {   this.radius = radius;  }  //方法的重载,参数不同  // 构造方法,无参构造  public circle() {   this.radius = 1;  }  // 求圆面积的方法  public double getArea() {   return radius * radius * Math.PI;  }  // 求圆周长的方法  public double getPerimeter() {   return 2 * Math.PI * radius;  }  public void setRadius(double newRadius) {   this.radius=newRadius;  }}package kk;public class Dmc {  public static void main(String[] args) {   circle circle1=new circle();   double area=circle1.getArea();   System.out.println(area);   circle circle2=new circle(10);   System.out.println(circle2.getArea());   System.out.println(circle1.getPerimeter());   System.out.println(circle2.getPerimeter());   double ridius=10;   double areaCircle=Math.PI*ridius*ridius;   System.out.println(areaCircle);   circle2.setRadius(5);   System.out.println(circle2.getArea());     }}

  

2 package kk;public class Scircle {  private double radius;  public Scircle() {   this.radius=1;  }  public Scircle(double radius){   this.radius=radius;  }  public double getArea() {   return Math.PI*radius*radius;  }  public double getPerimeter() {   return 2*Math.PI*radius;  }  public static void main(String[] args) {   Scircle cir1=new Scircle();   System.out.println("The area of the circle of radius "+cir1.radius+" is "+cir1.getArea());   Scircle cir2=new Scircle(10);   System.out.println("The area of the circle of radius "+cir2.radius+" is "+cir2.getArea());  }}

  

 3   package kk;public class TV { public int channel=1; public int volumeLevel=1; public boolean on=false; public void turnOn() {  on =true;  System.out.println("地址为"+new TV());  System.out.println("号的电视已经打开"); } public void turnOff() {  on=false;  System.out.println("电视已经关闭"); } public int getChannel() {  return channel; } public void setChannel(int channel) {  if(on) {   System.out.println("电视机已开,可开始调台");   if(channel>=1&&channel<=120) {    this.channel = channel;    System.out.println("频道已经调到 "+channel+" 号台");   }else {    System.out.println("你要调的频道不存在");   }  }else {   System.out.println("电视机关着的时候不能调台");  } } public int getVolumeLevel() {  return volumeLevel; } public void setVolumeLevel(int volumeLevel) {  if(on) {   System.out.println("电视机已开,声音大小可调");   if(volumeLevel>=1&&volumeLevel<=7) {    this.volumeLevel = volumeLevel;    System.out.println("声音的大小设置成 "+volumeLevel);   }   else {    System.out.println("音量大小超过范围");   }  }else {   System.out.println("电视机关着的时候不能调声音");  }   } public void channelUp() {  if(on&&channel<120) {   channel++;  } } public void channelDown() {  if(on&&channel>1) {   channel--;  } } public void volumeUp() {  if(on&&volumeLevel<7) {   volumeLevel++;  } } public void volumeDown() {  if(on&&volumeLevel>1) {   volumeLevel--;  } }  }package kk;public class CTV {  public static void main(String[] args) {  TV tv1=new TV();  tv1.turnOn();  tv1.setChannel(77);  tv1.setVolumeLevel(9);    TV tv2=new TV();  tv2.turnOn();  System.out.println("TV2's channel is "+tv2.channel+" and volume is "+tv2.volumeLevel);  tv2.channelUp();  System.out.println("TV2's channel is "+tv2.channel+" and volume is "+tv2.volumeLevel);  tv2.channelUp();  System.out.println("TV2's channel is "+tv2.channel+" and volume is "+tv2.volumeLevel);  tv2.channelUp();  System.out.println("TV2's channel is "+tv2.channel+" and volume is "+tv2.volumeLevel);  tv2.volumeUp();  System.out.println("TV2's channel is "+tv2.channel+" and volume is "+tv2.volumeLevel);  tv2.volumeUp();  System.out.println("TV2's channel is "+tv2.channel+" and volume is "+tv2.volumeLevel);  tv2.volumeUp();  System.out.println("TV2's channel is "+tv2.channel+" and volume is "+tv2.volumeLevel);    }}