24．编写一个Car类，具有String类型的属性品牌，具有功能drive； 定义其子类Aodi和Benchi，具有属性：价格、型号；具有功能：变速； 定义主类E，在其main方法中分别创建Aodi和Benchi的对象并测试对象的特 性。

package zhongqiuzuoye;

public class Car {

     String brand;

     public void drive()
     {}

}

package zhongqiuzuoye;

public class Aodi extends Car{

    public double price;
    public String model;
    public double speed;

    public Aodi(double price,String model,double speed)
    {
        this.price=price;
        this.model=model;
        this.speed=speed;
        System.out.println("价格为："+price+"\t型号为："+model+"\t初始速度为："+speed);
    }

    double setSpeed(double s)
    {
        speed+=s;
        System.out.println("当前车速为："+speed);
        return speed;
    }
}

package zhongqiuzuoye;

public class Benchi extends Car{

    public double price;
    public String model;
    public double speed;

    public Benchi(double price,String model,double speed)
    {
        this.price=price;
        this.model=model;
        this.speed=speed;
        System.out.println("价格为："+price+"\t型号为："+model+"\t初始速度为："+speed);
    }

    double setSpeed(double s)
    {
        speed+=s;
        System.out.println("当前车速为："+speed);
        return speed;
    }

}

package zhongqiuzuoye;

public class E {
    public static void main(String[] args) {

    Aodi a4=new Aodi(300000,"A4",40);
    a4.setSpeed(-10);

    Benchi e200=new Benchi(500000,"e200",50);
    e200.setSpeed(50);

}
}