Question

我有以下抽象类：

abstract class OutDoorGames
{
    protected String name;
    protected int num_players;
    protected int min_of_play;

    abstract void game (String a,int g,int r);
};

我希望public void game 函数将值分配给对象的数据成员。

这是实施 abstract void game (String a,int g,int r) ：

的类

class Cricket extends OuterDoorGames
{
    public void game (String name,int num_players,int min_of_play)
    {
        OutDoorGames::name = name ; 
        OutDoorGames::num_players = num_players ; 
        OutDoorGames::min_of_play = min_of_play ; 
    }
}

但它在编译时给出错误..

我也试过这个：

class Cricket extends OuterDoorGames
{
    public void game (String name,int num_players,int min_of_play)
    {
        this.name = name ; 
        this.num_players = num_players ; 
        this.min_of_play = min_of_play ; 
    }
}

这也行不通...... 我是Java新手......我该如何实现这个功能..... ??

Answer 1

class Cricket扩展了OuterDoorGames

如果您收到OuterDoorGames cannot be resolved to a type，那么这就是拼写错误。您的抽象类被命名为＆＃34; OutDoorGames＆＃34;。一旦你纠正了，你的板球课应该可以正常工作。

Answer 2

首先，你的名字是错的。注意你给父抽象类OutDoorGames的名字与你在扩展OuterDoorGames时所写的名称不同。

作为一种练习，您还可以尝试在父抽象类中创建一个构造函数，该抽象类设置3个成员，然后从子类的构造函数中调用它

此类用法的一个示例：

public abstract class Bicycle {

// the Bicycle class has three fields
public int cadence;
public int gear;
public int speed;

// the Bicycle class has one constructor
public Bicycle(int startCadence, int startSpeed, int startGear) {
    gear = startGear;
    cadence = startCadence;
    speed = startSpeed;
}

// the Bicycle class has four methods
public void setCadence(int newValue) {
    cadence = newValue;
}

public void setGear(int newValue) {
    gear = newValue;
}

public void applyBrake(int decrement) {
    speed -= decrement;
}

public void speedUp(int increment) {
    speed += increment;
}    }

    public class MountainBike extends Bicycle {

    // the MountainBike subclass adds one field
    public int seatHeight;

    // the MountainBike subclass has one constructor
    public MountainBike(int startHeight,
                        int startCadence,
                        int startSpeed,
                        int startGear) {
        super(startCadence, startSpeed, startGear);
        seatHeight = startHeight;
    }   

    // the MountainBike subclass adds one method
    public void setHeight(int newValue) {
        seatHeight = newValue;
    }   
}

注意激活父类构造函数的super调用。只需将其更改为接受父类中的3个参数

Answer 3

我能看到的唯一错误是第二个错误是类名错误。您定义的第一个类（您的抽象类）称为“OutDoorGames”，但您正在尝试扩展“OuterDoorGames”。

如何实现使用父类数据成员的抽象函数

3 个答案: