第一题

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

第二题

写一个Person类，有编号id,姓名name,职位job。

构造方法带三个参数。

方法：

登陆login

注册register

自我介绍talk

写一个学生Student类继承Person类，方法有：考试test

属性有：学费money

写一个老师Teacher类继承Person类，

属性有 工资salary

方法有：工作work

写一个测试类TestPerson，测试学生和老师

学生：姓名-张三  职位-学生  学费-18000

老师：姓名-李四  职位-老师  工资-8000

注册、登陆输出就可以，自我介绍输出属性?

第三题

定义一个父类:形状类Shapes，里面有两个方法，分别是求面积和周长。

定义一个子类：矩形Rectangle

定义一个子类：三角形 Triagle

定义一个子类：圆 Circle

定义一个测试类：传入圆的半径4 输出周长和面积

                传入矩形的长和宽4，5 输出周长和面积

                传入三角形三边：3，4，5 输出周长和面积

第一题：
package homework;

public class Auto {
    protected int gears;
    protected String color;
    protected double weight;
    protected double speed;
    
    public Auto() {
        this.gears=4;
        this.color="黄色";
        this.weight=200;
        this.speed=50;
    }

    public Auto(int gears, String color, double weight, double speed) {
        super();
        this.gears = gears;
        this.color = color;
        this.weight = weight;
        this.speed = speed;
    }
    public void speedUp()
    {
        speed+=5;
        System.out.println("加速至"+speed);
    }
    public void speedDown()
    {
        speed-=5;
        System.out.println("减速至"+speed);
    }
    public void stop()
    {
        speed=0;
        System.out.println("汽车停止，速度是"+speed);
    }
    
}

package homework;

public class Car extends Auto{
    protected String kongtiao;
    protected String CD;
    
    public Car() {
        super();
        kongtiao="品牌1空调";
        CD="CD1";
    }
    
    public Car(int gears, String color, double weight, double speed,String kongtiao, String cD) {
        super(gears, color, weight, speed);
        this.kongtiao = kongtiao;
        CD = cD;
    }
    
    @Override
    public void speedUp(){
        super.speed+=10;
        System.out.println("加速至"+speed);
    }
    @Override
    public void speedDown() {
        speed-=10;
        System.out.println("减速至"+speed);
    }
    
    public void information()
    {
        System.out.println("当前是"+color+"的"+gears+"轮"+color+"的重"+weight+"的配有"+kongtiao+"和"+CD+"的车子，当前时速为"+speed);
    }
    
}
package homework;

public class TestAuto {
    public static void main(String[] args) {
        Car car=new Car();
        car.information();
        car.speedDown();
        car.speedUp();
        car.stop();
        System.out.println();
        Car car2=new Car(3, "白色", 300, 70,"品牌2空调", "CD2");
        car2.information();
        car2.speedDown();
        car2.speedUp();
        car.stop();
    }
}



第二题：
package homework;

public class Person {
    protected int id;
    protected String name;
    protected String job;
    
    public Person(int id, String name, String job) {
        this.id = id;
        this.name = name;
        this.job = job;
    }
    public void login()
    {
        System.out.println("登陆成功");
    }
    public void register()
    {
        System.out.println("注册成功");
    }
    public void talk()
    {
        System.out.println("大家好！我是"+name+",编号是"+id+",职位是"+job);
    }
}

package homework;

public class Student extends Person {
    protected double money;
    
    public Student(int id, String name, String job, double money) {
        super(id, name, job);
        this.money = money;
    }

    public void test()
    {
        System.out.println("我在考试");
    }
    public void information()
    {
        System.out.println("姓名-"+name+"\t职位-"+job+"\t学费"+money);
    }
    
}

package homework;

public class Teacher extends Person{
    protected double salary;
    
    public Teacher(int id, String name, String job, double salary) {
        super(id, name, job);
        this.salary = salary;
    }

    public void work()
    {
        System.out.println("我在工作");
    }
    public void information()
    {
        System.out.println("姓名-"+name+"\t职位-"+job+"\t工资"+salary);
    }
}
package homework;

public class TestPerson {

    public static void main(String[] args) {
        Student stu=new Student(1, "张三", "学生", 18000);
        stu.login();
        stu.register();
        stu.talk();
        stu.test();
        stu.information();
        System.out.println();
        Teacher tea=new Teacher(2, "张老师", "老师", 8000);
        tea.login();
        tea.register();
        tea.talk();
        tea.information();
    }

}



第三题：
package homework;

public class Shapes {
    public void area()
    {
        System.out.println("求面积");
    }
    public void zhouChang()
    {
        System.out.println("求周长");
    }
}
package homework;

public class Rectangle extends Shapes {
    private int chang;
    private int kuan;
    
    public Rectangle(int chang, int kuan) {
        super();
        this.chang = chang;
        this.kuan = kuan;
    }
    @Override
    public void area() {
        System.out.println("长方形面积是"+chang*kuan);
    }
    @Override
    public void zhouChang() {
        System.out.println("长方形周长是"+(chang+kuan)*2);
    }
    
}
package homework;

public class Circle extends Shapes{
    private int a;

    public Circle(int a) {
        super();
        this.a = a;
    }
    @Override
    public void area() {
        System.out.println("圆形面积是"+a*a*Math.PI);
    }
    @Override
    public void zhouChang() {
        System.out.println("圆形周长是"+a*Math.PI*2);
    }
    
    
    
}
package homework;

public class Triagle extends Shapes {
    private int a;
    private int b;
    private int c;

    
    public Triagle(int a, int b, int c) {
        super();
        this.a = a;
        this.b = b;
        this.c = c;
    }
    public void area() {
        System.out.println("三角形面积是"+Math.sqrt((a+b+c)*(a+b-c)*(a+c-b)*(b+c-a))/4);
    }
    @Override
    public void zhouChang() {
        System.out.println("三角形周长是"+(a+b+c));
    }
}
package homework;

public class TestShapes {

    public static void main(String[] args) {
        Circle circle=new Circle(1);
        circle.area();
        circle.zhouChang();
        Rectangle rectangle=new Rectangle(2, 3);
        rectangle.area();
        rectangle.zhouChang();
        Triagle triagle=new Triagle(3, 4, 5);
        triagle.area();
        triagle.zhouChang();
    }

}