一、交通工具类

要求：

• 定义一个Vehicle类，其中有如下属性：

  • 速度
  • 体积
  • 方法移动
  • 设置速度
  • 加速
  • 减速

• 在测试类中实例化一个交通工具对象，并通过方法给它初始化speed和size的值并打印，另外调用加速减速的方法对速度进行修改。

public class Vehicle {
    private double speed;
    private double size;
    public void move(){
        System.out.println("开始运行！");
    }
    public void speedUp(double a){
            this.speed=this.speed+a;
    }

    public Vehicle(double speed, double size) {
        this.speed = speed;
        this.size = size;
    }

    public void speedDown(double a){
        this.speed=speed-a;
    }

    public double getSpeed() {
        return speed;
    }

    public void setSpeed(double speed) {
        this.speed = speed;
    }

    public Vehicle() {
    }

    public double getSize() {
        return size;
    }

    public void setSize(double size) {
        this.size = size;
    }
}

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/**
 * Created with IntelliJ IDEA.
 * Description:
 * User: Lenovo
 * Date: 2022-06-30
 * Time: 10:21
 */
public class Test02 {
    public static void main(String[] args) {
        //通过无参数构造方法创建对象
        Vehicle v=new Vehicle(120,5);
        v.setSize(5);
        v.setSpeed(120);
        System.out.println(v.getSpeed());
        System.out.println(v.getSize());
        //通过有参数的构造方法创建对象
        Vehicle v1=new Vehicle(130,4);
        //调用加速方法
        v.speedUp(20);
        System.out.println("加速后的speed:"+v.getSpeed());
        //调用减速方法
        v.speedDown(10);
        System.out.println("减速后的speed:"+v.getSpeed());
    }
}

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二、实现简单的计算器

编写一个程序，模拟简单的计算器

• 定义名为Number的类，其中有两个整型数据成员n1和n2应该声明为私有。
• 编写构造方法赋予n1和n2初值
• 再为该类定义：加，减，乘，除运算
• 在main方法当中创建Number类的对象调用各个方法并显示计算结果

public class Number {
    private double n1;
    private double n2;

    public Number(double n1, double n2) {
        this.n1 = n1;
        this.n2 = n2;
    }
    public Number() {
    }

    public double getN1() {
        return n1;
    }

    public void setN1(double n1) {
        this.n1 = n1;
    }

    public double getN2() {
        return n2;
    }

    public void setN2(double n2) {
        this.n2 = n2;
    }

    public void addition(){
        double result=n1+n2;
        System.out.println(n1+" + "+n2+" = "+result);
    }
    public void subtraction(){
        double result=n1-n2;
        System.out.println(n1+" - "+n2+" = "+result);
    }
    public void multiplication(){
        double result=n1*n2;
        System.out.println(n1+" * "+n2+" = "+result);
    }
    public void division(){
        double result=n1/n2;
        System.out.println(n1+" / "+n2+" = "+result);
    }
}
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public class Test01 {
    public static void main(String[] args) {
        Number n=new Number();
        n.setN2(20);
        n.setN1(110);
        n.addition();
        n.division();
        n.multiplication();
        n.subtraction();
    }
}
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三、时间类

• 定义名字为MyTime的类，其中应该有三个整型成员：时，分，秒
• 为了保证数据的安全性，这三个成员应该定义为私有的
• 为MyTime类定义构造方法以方便创建对象时初始化成员变量
• 再定义display方法用于将时间信息打印出来

这里只对秒的加法做了取模和取余，因为是数学的问题：

public class MyTime {
    private int hour;
    private int minute;
    private int second;

    public int getHour() {
        return hour;
    }

    public void setHour(int hour) {
        this.hour = hour;
    }

    public int getMinute() {
        return minute;
    }

    public void setMinute(int minute) {
        this.minute = minute;
    }

    public int getSecond() {
        return second;
    }

    public void setSecond(int second) {
        this.second = second;
    }

    public MyTime() {
    }

    public MyTime(int hour, int minute, int second) {
        this.hour = hour;
        this.minute = minute;
        this.second = second;
    }

    public void addSecond(int sec){
        int oldSec=this.getSecond();
        int newSec=oldSec+sec;
        if(newSec<60){
            this.setSecond(newSec);
        }else if(newSec==60){
            this.setSecond(0);
            this.addMinute(1);
        }else{
            this.setMinute(minute+newSec/60);
            this.setSecond(newSec%60);
        }
    }
    public void addMinute(int min){
        minute=minute+min;
    }
    public void addHour(int hou){
        hour=hour+hou;
    }
    public void subSecond(int sec){
        second=second-sec;
    }
    public void subMinute(int min){
        minute=minute-min;
    }
    public void subHour(int hou){
        hour=hour-hou;
    }
    public void display(){
        System.out.println("现在的时间是"+this.getHour()+"时"+this.getMinute()+"分"+this.getSecond()+"分");
    }
}
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public class Test02 {
    public static void main(String[] args) {
        MyTime m=new MyTime();
        m.setHour(10);
        m.setMinute(20);
        m.setSecond(30);
        m.display();
        m.addHour(1);
        m.addMinute(2);
        m.addSecond(113);
        m.display();
    }
}
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