// 抽象父类 Vehicle
public abstract class Vehicle {
    public abstract void run();
}

// 子类 Car
public class Car extends Vehicle {
    @Override
    public void run() {
        System.out.println("汽车在公路上行驶，速度 100km/h");
    }
}

// 子类 Bike
public class Bike extends Vehicle {
    @Override
    public void run() {
        System.out.println("自行车在非机动车道骑行，速度 15km/h");
    }
}

// 子类 Truck
public class Truck extends Vehicle {
    @Override
    public void run() {
        System.out.println("卡车在公路上缓慢行驶，速度 60km/h");
    }
}

// 测试主类
public class VehicleTest {
    public static void main(String[] args) {
        System.out.println("=== 进阶题测试 ===");
        // 创建 Vehicle 数组，存放不同车辆
        Vehicle[] vehicles = {
            new Car(),
            new Bike(),
            new Truck()
        };

        // 遍历调用 run() 方法
        for (Vehicle v : vehicles) {
            v.run();
        }
    }
}