本文目录一览:
这道Java题怎么做?
首先定义Point类
public class Point {
private int x;
private int y;
private int z;
//无参构造
public Point(){}
//带参数的构造函数,用于初始化坐标
public Point(int x, int y, int z) {
this.x = x;
this.y = y;
this.z = z;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
public int getZ() {
return z;
}
public void setZ(int z) {
this.z = z;
}
}
编写Main方法,执行,验证
import java.lang.Math;
public class Main {
public static double distancePOW(Point p1,Point p2)
{
return Math.pow(p1.getX()-p2.getX(),2)+Math.pow(p1.getY()-p2.getY(),2)+Math.pow(p1.getZ()-p2.getZ(),2);
}
public static void main(String[] args){
Point point1 = new Point(1,2,3);
Point point2 = new Point(5,0,0);
double distancePOW = distancePOW(point1,point2);
System.out.println("两个三维坐标点之间的距离的平方为"+distancePOW);
}
}
输出结果:两个三维坐标点之间的距离的平方为29.0
java这道题怎么做?
// 建立一个汽车Auto类,包括轮胎个数,汽车颜色,车身重量、速度等成员变量。并通过不同的构造方法创建实例。
// 至少要求: 汽车能够加速,减速,停车。再定义一个小汽车类Car,继承Auto,并添加空调、CD等成员变量,覆盖加速,减速的方法
class Auto {
public int 轮胎数量;
public String 汽车颜色;
public double 车身重量;
public double 速度;
Auto() {
// 无参构造
}
Auto(int 轮胎数量, String 汽车颜色, double 车身重量, double 速度) {
// 有参构造
this.轮胎数量 = 轮胎数量;
this.汽车颜色 = 汽车颜色;
this.车身重量 = 车身重量;
this.速度 = 速度;
}
public void 加速() {
System.out.println("Auto加速");
}
public void 减速() {
System.out.println("Auto减速");
}
public void 停车() {
System.out.println("Auto停车");
}
}
class Car extends Auto {
public String 空调;
public String CD;
public void 加速() {
System.out.println("Car加速");
}
public void 减速() {
System.out.println("Car减速");
}
}
这道java题应该怎么做?
Java源代码:
public class Test {
public static void main(String[] args) {
Point p1 = new Point(4, 5);
System.out.printf("点p坐标为(%f,%f)n", p1.getX(), p1.getY());
p1.setX(3);
p1.setY(4);
System.out.printf("重置后点p坐标为(%f,%f)n", p1.getX(), p1.getY());
System.out.printf("点(%f, %f)到原点的距离的平方为%fn", p1.getX(), p1.getY(),
p1.distance());
Point p2 = new Point(1, 2);
System.out.printf("点(%f,%f)到点(%f,%f)的距离的平方为%fn", p1.getX(),
p1.getY(), p2.getX(), p2.getY(), p1.distance(p2));
}
}
class Point {
protected double x;
protected double y;
public Point(){
}
public Point(double x, double y) {
this.x = x;
this.y = y;
}
public void setX(double x) {
this.x = x;
}
public double getX() {
return this.x;
}
public void setY(double y) {
this.y = y;
}
public double getY() {
return this.y;
}
public double distance() {
return Math.pow(x, 2) + Math.pow(y, 2);
}
public double distance(Point p) {
return Math.pow(this.x - p.x, 2) + Math.pow(this.y - p.y, 2);
}
}
运行测试:
请问这个Java题怎么做?
按照题目要求编写的Java程序如下
import java.util.Scanner;
class RadiusException extends Exception{
public RadiusException(String message){
super(message);
}
}
public class Circle{
public double area(double r) throws RadiusException{
if(r0)
throw new RadiusException("输入错误");
else
return Math.PI*r*r;
}
public static void main(String[] args){
System.out.print("请输入圆的半径r:");
try{
Scanner sc=new Scanner(System.in);
double r=sc.nextDouble();
Circle c=new Circle();
System.out.println("圆的面积为"+c.area(r));
sc.close();
}catch(RadiusException re){
System.out.println(re.getMessage());
}
}
}
这道java题怎么做?
Java参考源代码:
import java.awt.FlowLayout;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import javax.swing.*;
public class Test10 extends JFrame implements ActionListener {
protected JList lstLeft = null;
protected JList lstRight = null;
protected JButton btnAdd = null;
protected String[] arr = {"新闻", "娱乐", "体育", "教育"};
public Test10() {
super("列表框");
initComponent();
this.setSize(400, 300);
this.setVisible(true);
this.setLayout(new FlowLayout());
this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
public void initComponent() {
lstLeft = new JList(arr);
lstRight = new JList();
btnAdd = new JButton("");
this.add(lstLeft);
this.add(btnAdd);
this.add(lstRight);
lstLeft.setSelectionMode(ListSelectionModel.MULTIPLE_INTERVAL_SELECTION);
btnAdd.addActionListener(this);
}
public static void main(String[] args) {
new Test10();
}
@Override
public void actionPerformed(ActionEvent e) {
Object[] items = lstLeft.getSelectedValues();
DefaultListModel model = new DefaultListModel();
lstRight.setModel(model);
model.removeAllElements();
for(Object value : items) {
model.addElement(value);
}
}
}
运行测试:
请点击输入图片描述