电视机 圆
//1.
//例题9.1 制作圆类，根据圆的半径求出周长及面积
package com.atlu;
//抽象的方法构成类，把属性和方法进行封装
public class Circle {
// 两个方面一个是字段也称属性，另一个是方法，也称实现的功能
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;
}
}
public class DemoCircle {
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());
}
}
//作业2：把上边的两个圆的类合并成一个类，并实现同样功能
package com.atlu;
public class SimpleCircle {
private double radius;
public SimpleCircle() {
this.radius=1;
}
public SimpleCircle(double radius){
this.radius=radius;
}
public double getArea() {
// TODO Auto-generated method stub
return Math.PI*radius*radius;
}
public double getPerimeter() {
return 2*Math.PI*radius;
}
public static void main(String[] args) {
SimpleCircle cir1=new SimpleCircle();
System.out.println("The area of the circle of radius "+cir1.radius+" is "+cir1.getArea());
System.out.println("The perimeter of the circle of radius "+cir1.radius+" is "+cir1.getPerimeter());
SimpleCircle cir2=new SimpleCircle(10);
System.out.println("The area of the circle of radius "+cir2.radius+" is "+cir2.getArea());
System.out.println("The perimeter of the circle of radius "+cir2.radius+" is "+cir2.getPerimeter());
}
}
3.
/例题9.3 造一台电视机，并且实现调频道和调声音大小功能
public class TV {
public int channel=1;
public int volumeLevel=1;
public boolean on=false;
public TV() {
}
public void turnOn() {
on =true;
System.out.println("叮咚！");
}
public void turnOff() {
on=false;
System.out.println("呜呜！");
}
public int getChannel() {
return channel;
}
public void setChannel(int channel) {
if(on) {
System.out.println("你想看啥！");
if(channel>=1&&channel<=120) {
this.channel = channel;
System.out.println("卡到 "+channel+" 台了！");
}else {
System.out.println("信号大概去外星球了！！");
}
}else {
System.out.println("滋滋！");
}
}
public int getVolumeLevel() {
return volumeLevel;
}
public void setVolumeLevel(int volumeLevel) {
if(on) {
System.out.println("想让我大点声说话吗，偏不，哈哈！");
if(volumeLevel>=1&&volumeLevel<=7) {
this.volumeLevel = volumeLevel;
System.out.println("已经 "+volumeLevel+" 大小说话了啊。");
}
}else {
System.out.println("咔咔！");
}
}
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--;
}
}
}
//测试电视机的类
package com.atlu;
public class TestTv {
public static void main(String[] args) {
TV tv1=new TV();
tv1.turnOff();
tv1.setChannel(30);
tv1.setVolumeLevel(3);
TV tv2=new TV();
tv2.turnOn();
tv2.setChannel(130);
// tv2.setVolumeLevel(3);
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);
}
}
4
package com.atlu;
public class StaticDemo {
public static void main(String args[]){
new StaticDemo().fun();
}
public void fun(){
System.out.println("Hello World!!!");
}
}
5
package com.atlu;
public class DemoPerson {
private String name;
private int age;
public DemoPerson(String name,int age){
this.name=name;
this.age=age;
}
public boolean compare(DemoPerson1 per){
if(this.name.equals(per.name)&&this.age==per.age){
return true;
}else{
return false;
}
}
public String getName(){
return this.name;
}
public int getAge(){
return this.age;
}
public static void main(String args[]){
DemoPerson1 per1=new DemoPerson1("张三",30);
DemoPerson1 per2=new DemoPerson1("张三",30);
if(per1.compare(per2)){
System.out.println("是同一个人！");
}
}
};
6.
package com.atlu;
public class DemoPerson1 {
String name;
int age;
public DemoPerson1(String name,int age){
this.name=name;
this.age=age;
}
public boolean compare(DemoPerson1 per){
if(this==per){//地址相等
return true;
}
if(this.name.equals(per.name)&&this.age==per.age){
return true;
}else{
return false;
}
}
public String getName(){
return this.name;
}
public int getAge(){
return this.age;
}
public static void main(String args[]){
DemoPerson1 per1=new DemoPerson1("张三",30);
DemoPerson1 per2=new DemoPerson1("张三",30);
if(per1.compare(per2)){
System.out.println("是同一个人！");
}
}
};
7.
package com.atlu;
class DemoPerson2{
private String name;
private int age;
public DemoPerson2(String name,int age){
this.name=name;
this.age=age;
}
public void fun(DemoPerson2 temp){
temp.name="李四";
temp.age=33;
}
public String getName(){
return this.name;
}
public int getAge(){
return this.age;
}
public static void main(String args[]){
DemoPerson2 per=new DemoPerson2("张三",30);
per.fun(per);{
System.out.println(per.getName()+"-->"+per.getAge());
}
}
}
8.
package com.atlu;
class DemoPerson3{
private String name;
private int age;
public DemoPerson3(String name,int age){
this.name=name;
this.age=age;
}
public String getName(){
return this.name;
}
public int getAge(){
return this.age;
}
public static void main(String args[]){
DemoPerson3 per1=new DemoPerson3("张三",30);
DemoPerson3 per2=new DemoPerson3("张三",30);
if(per1.getName().equals(per2.getName())&&per1.getAge()==per2.getAge()){
System.out.println("是同一个人！");
}
}
};
