用Java定义一个汽车类，要求有颜色、轮胎数量、速度等成员属性，并且汽车要有加速、减速、停车方法 定义一个小汽车类继承汽车类，重写相关方法，并添加载人方法，定义一个重卡类，继承汽车并重写 相关方法，并且还有载货方法，小汽车和重卡都有变形方法（接口）

汽车类：

public class Car {
    private String color;
    private int numOfWheels;
    private int speed;

    public Car(String color, int numOfWheels, int speed) {
        this.color = color;
        this.numOfWheels = numOfWheels;
        this.speed = speed;
    }

    public void accelerate(int amount) {
        speed += amount;
    }

    public void decelerate(int amount) {
        speed -= amount;
    }

    public void stop() {
        speed = 0;
    }
}

小汽车类：

public class Car extends Vehicle {
    private int numOfPassengers;

    public Car(String color, int numOfWheels, int speed, int numOfPassengers) {
        super(color, numOfWheels, speed);
        this.numOfPassengers = numOfPassengers;
    }

    public void accelerate(int amount) {
        if (speed + amount <= 120) {
            super.accelerate(amount);
        } else {
            System.out.println("Cannot accelerate to that speed.");
        }
    }

    public void decelerate(int amount) {
        if (speed - amount >= 0) {
            super.decelerate(amount);
        } else {
            System.out.println("Cannot decelerate to that speed.");
        }
    }

    public void stop() {
        super.stop();
        numOfPassengers = 0;
    }

    public void carryPassengers(int numOfPassengers) {
        this.numOfPassengers = numOfPassengers;
    }

    public void transform() {
        System.out.println("The car has transformed into a robot!");
    }
}

重卡类：

public class Truck extends Vehicle {
    private int maxCargoWeight;

    public Truck(String color, int numOfWheels, int speed, int maxCargoWeight) {
        super(color, numOfWheels, speed);
        this.maxCargoWeight = maxCargoWeight;
    }

    public void accelerate(int amount) {
        if (speed + amount <= 80) {
            super.accelerate(amount);
        } else {
            System.out.println("Cannot accelerate to that speed.");
        }
    }

    public void decelerate(int amount) {
        if (speed - amount >= 0) {
            super.decelerate(amount);
        } else {
            System.out.println("Cannot decelerate to that speed.");
        }
    }

    public void stop() {
        super.stop();
        System.out.println("All cargo has been unloaded.");
    }

    public void carryCargo(int weight) {
        if (weight <= maxCargoWeight) {
            System.out.println("Cargo loaded.");
        } else {
            System.out.println("Cargo too heavy.");
        }
    }

    public void transform() {
        System.out.println("The truck has transformed into a giant robot!");
    }
}

变形接口：

public interface Transformable {
    void transform();
}