编写一个Car类，具有final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 b;

public class Car {
      public final static Car pinpai=new Car();
      public static Car instance()
      {
        return pinpai;
      }
      public void drive()
      {
          System.out.println("请安全驾驶！");
      }
}

package b;

public class Aodi extends Car {
    private String price;
    private String xinghao;
    public String getPrice() {
        return price;
    }
    public void setPrice(String price) {
        this.price = price;
    }
    public String getXinghao() {
        return xinghao;
    }
    public void setXinghao(String xinghao) {
        this.xinghao = xinghao;
    }
    public void biansu(int a)
    {
        if(a>0)
        {
            System.out.println("加速");
        }
        else if(a<0)
        {
            System.out.println("减速");
        }
        else
        {
            System.out.println("匀速前进");
        }

    }

}

package b;

public class Benchi extends Car {
    private String price;
    private String xinghao;
    public String getPrice() {
        return price;
    }
    public void setPrice(String price) {
        this.price = price;
    }
    public String getXinghao() {
        return xinghao;
    }
    public void setXinghao(String xinghao) {
        this.xinghao = xinghao;
    }
    public void biansu(int a)
    {
        if(a>0)
        {
            System.out.println("加速");
        }
        else if(a<0)
        {
            System.out.println("减速");
        }
        else
        {
            System.out.println("匀速前进");
        }

    }
}

package b;

public class E {

    public static void main(String[] args) {
        Aodi aodi=new Aodi();
        aodi.setXinghao("奥迪Q7");
        aodi.setPrice("110万");
        System.out.println(aodi.getXinghao());
        System.out.println(aodi.getPrice());
        aodi.biansu(90);
        aodi.drive();
        Benchi benchi=new Benchi();
        benchi.setXinghao("迈巴赫");
        benchi.setPrice("200万");
        System.out.println(benchi.getXinghao());
        System.out.println(benchi.getPrice());
        benchi.biansu(-90);
        benchi.drive();
    }

}