用Java实现，求教各位大佬

[໊ۖ͡✾ۖ͡黎夏ೄ೨]

（1）创建Car类： 属性：车牌号(String)，车速(int)，载重量(double) 功能：设置和返回车牌号、设置和返回车速、设置和返回载重量、加速(车速自增)、减速(车速自减)。 编写两个构造方法：一个无参，在方法中将车牌号设置“XX6666”，速度设置为55，载重量设置为777.77；一个有参，为所有属性赋值； （2）创建对象： 创建Car类的两个对象，使创建第一个对象时调用无参的构造方法，并调用成员方法修改其车牌为“YY8888”，让其加速。使创建第二个时调用有参的构造方法，使其车牌为“ZZ9999”,车速为100,载重为600，并让其减速。

[往后余生是你]

public class Car {
    private String busno;//车牌号
    private int speed;//车速
    private double weight;//载重量
    public String getBusno() {
        return busno;
    }

    public void setBusno(String busno) {
        this.busno = busno;
    }

    public int getSpeed() {
        return speed;
    }

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

    public double getWeight() {
        return weight;
    }

    public void setWeight(double weight) {
        this.weight = weight;
    }

    @Override
    public String toString() {
        return "Car{" +
                "busno='" + busno + '\'' +
                ", speed=" + speed +
                ", weight=" + weight +
                '}';
    }

    /**
     * 带参构造函数
     * @param busno
     * @param speed
     * @param weight
     */
    public Car(String busno, int speed, double weight) {
        this.busno = busno;
        this.speed = speed;
        this.weight = weight;
    }

    /**
     * 无参构造函数
     */
    public Car() {
        this.busno = "XX6666";
        this.speed = 55;
        this.weight = 777.77;
    }

    public static void main(String[] args) {
        Car car1=new Car();//无参构造创建对象
        car1.setBusno("YY8888");//
        Car car2=new Car("ZZ9999",100,600);
        System.out.println("car1==="+car1);
        System.out.println("car2==="+car2);
    }

}

[LuckyWW123]

引用 1 楼 往后余生是你 的回复:

public class Car {
    private String busno;//车牌号
    private int speed;//车速
    private double weight;//载重量
    public String getBusno() {
        return busno;
    }

    public void setBusno(String busno) {
        this.busno = busno;
    }

    public int getSpeed() {
        return speed;
    }

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

    public double getWeight() {
        return weight;
    }

    public void setWeight(double weight) {
        this.weight = weight;
    }

    @Override
    public String toString() {
        return "Car{" +
                "busno='" + busno + '\'' +
                ", speed=" + speed +
                ", weight=" + weight +
                '}';
    }

    /**
     * 带参构造函数
     * @param busno
     * @param speed
     * @param weight
     */
    public Car(String busno, int speed, double weight) {
        this.busno = busno;
        this.speed = speed;
        this.weight = weight;
    }

    /**
     * 无参构造函数
     */
    public Car() {
        this.busno = "XX6666";
        this.speed = 55;
        this.weight = 777.77;
    }

    public static void main(String[] args) {
        Car car1=new Car();//无参构造创建对象
        car1.setBusno("YY8888");//
        Car car2=new Car("ZZ9999",100,600);
        System.out.println("car1==="+car1);
        System.out.println("car2==="+car2);
    }

}

在楼上的代码中再加一个无参构造函数
public car(){

}
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