java编程多态练习停车场收费系统

以下是Java编程实现停车场收费系统的多态练习题解答：

// 定义车辆类
class Vehicle {
    protected String type; // 车型
    protected int hours; // 停车时间

    public Vehicle(String type, int hours) {
        this.type = type;
        this.hours = hours;
    }

    // 计算停车费用
    public double calculateFee() {
        return 0;
    }
}

// 定义客车类
class Bus extends Vehicle {
    public Bus(int hours) {
        super("客车", hours);
    }

    // 重写计算停车费用方法
    public double calculateFee() {
        return hours * 15;
    }
}

// 定义货车类
class Truck extends Vehicle {
    public Truck(int hours) {
        super("货车", hours);
    }

    // 重写计算停车费用方法
    public double calculateFee() {
        return hours * 12;
    }
}

// 定义轿车类
class Car extends Vehicle {
    public Car(int hours) {
        super("轿车", hours);
    }

    // 重写计算停车费用方法
    public double calculateFee() {
        return hours * 8;
    }
}

// 定义停车场类
class ParkingLot {
    private Vehicle[] vehicles; // 车辆数组
    private int count; // 车辆数量

    public ParkingLot() {
        vehicles = new Vehicle[100];
        count = 0;
    }

    // 添加车辆
    public void addVehicle(Vehicle vehicle) {
        vehicles[count++] = vehicle;
    }

    // 计算总停车费用
    public double calculateTotalFee() {
        double totalFee = 0;
        for (int i = 0; i < count; i++) {
            totalFee += vehicles[i].calculateFee();
        }
        return totalFee;
    }
}

// 测试类
public class Test {
    public static void main(String[] args) {
        ParkingLot parkingLot = new ParkingLot();
        parkingLot.addVehicle(new Bus(2));
        parkingLot.addVehicle(new Truck(3));
        parkingLot.addVehicle(new Car(4));
        System.out.println("总停车费用为：" + parkingLot.calculateTotalFee()); // 输出：总停车费用为：119.0
    }
}