abstract class Vehicle {
    public abstract void run();
}

class Car extends Vehicle {
    @Override
    public void run() {
        System.out.println("🚗 小汽车在公路上飞驰");
    }
}

class Bike extends Vehicle {
    @Override
    public void run() {
        System.out.println("🚲 自行车在林荫道骑行");
    }
}

class Truck extends Vehicle {
    @Override
    public void run() {
        System.out.println("🚚 大卡车在运送货物");
    }
}

public class VehicleTest {
    public static void main(String[] args) {
        Vehicle[] vehicles = {
            new Car(),
            new Bike(),
            new Truck()
        };

        for (Vehicle v : vehicles) {
            v.run(); 
        }
    }
}