用Java实现为某研究所编写一个通用程序，用来计算每一种交通工具运行1000公里所需的时间，已知每种交通工具的参数都是3个整数A、B、C的表达式。现有两种工具：Car007 和Plane，其中Car007 的速度运算公式为：A*B/C，Plane 的速度运算公式为：A+B+C。需要编写三个类：ComputeTime.java,Plane.java,Car007.java和接口Common.java，要求在未来如果增加第3种或多种交通工具的时候，不必修改以前的任何程序，只需要编写新的交通工具的程序。其运行过

程如下：

1. Common.java

public interface Common {
    double computeTime(int distance);
}

2. ComputeTime.java

public class ComputeTime {
    public static void main(String[] args) {
        int distance = 1000;
        Car007 car = new Car007(60, 5, 2);
        Plane plane = new Plane(300, 200, 100);

        double carTime = car.computeTime(distance);
        double planeTime = plane.computeTime(distance);

        System.out.println("Car007: " + carTime + " hours");
        System.out.println("Plane: " + planeTime + " hours");
    }
}

3. Car007.java

public class Car007 implements Common {
    private int A;
    private int B;
    private int C;

    public Car007(int A, int B, int C) {
        this.A = A;
        this.B = B;
        this.C = C;
    }

    public double computeTime(int distance) {
        double speed = A * B / (double) C;
        return distance / speed;
    }
}

4. Plane.java

public class Plane implements Common {
    private int A;
    private int B;
    private int C;

    public Plane(int A, int B, int C) {
        this.A = A;
        this.B = B;
        this.C = C;
    }

    public double computeTime(int distance) {
        double speed = A + B + C;
        return distance / speed;
    }
}

如果需要增加第3种或多种交通工具，只需要编写一个实现了Common接口的类即可，不需要修改以前的任何程序。