Question

我的基本class如下：

template<typename aGamePieceBase> class GamePiece : public aGamePieceBase
{
public:
    // Each GamePiece contains a definition of the base class from which it was derived
    typedef aGamePieceBase gamePieceBase

    // Returns this piece's sprite
    virtual sf::Sprite* getSprite()
    {
        return m_pSprite;
    }
protected:
    sf::Sprite* m_pSprite;
}

还有派生的class：

class Horse : public GameBoard::GamePiece< GameBoard::GamePieceBase >
{
public:
    virtual sf::Sprite* getSprite() override
    {
        // Do stuff
    }
};

但是我遇到Horse::getSprite减速时出现的错误用override声明的成员函数不会覆盖基类成员

为什么getSprite在Horse中不可用？

GamePieceBase如下：

class GamePieceBase : public GameEventHandler
{
public:
    // Called when the GamePiece has been added to the GameBoard 
    template<typename aTileBase> virtual void onPieceCreate( Tile<aTileBase> *startingLocation ){}
    // Called when the GamePiece has been removed from the GameBoard
    virtual void onPieceRemove(){}
    // Called when the user has selected this GamePiece
    virtual void onPieceSelect(){}
    // Called when the user has de-selected this GamePiece
    virtual void onPieceDeselect(){}
    // Called when this GamePiece has moved on the board
    template<typename originTileBase, typename destinationTileBase> virtual void onPieceMove( Tile<originTileBase>* originTileBase, Tile<destinationTileBase>* pDestinationTile ){}
};

编辑：输出日志表明存在内部编译器error，但未提供许多详细信息。我正在对此进行调查

Answer 1

这对我有用：

class GamePieceBase
{
public:
    // Called when the GamePiece has been added to the GameBoard 
};


template<typename aGamePieceBase> class GamePiece : public aGamePieceBase
{
public:
    // Each GamePiece contains a definition of the base class from which it was derived
//  typedef aGamePieceBase gamePieceBase

    // Returns this piece's sprite
    virtual int getSprite()
    {
        return 0;
    }
protected:

};


class Horse : public GamePiece< GamePieceBase >
{
public:
    virtual int getSprite() override
    {
        return 0;
    }
};

但是，最好写：

int getSprite() override

写显式virtual，override或final是自记录文档，使编译器能够捕获基类和派生类之间类型和/或名称的不匹配。但是，写这三者中的一个以上既多余又是潜在的错误源。 C++ CoreGuidelines C.128

Answer 2

问题出在线

typedef aGamePieceBase gamePieceBase

在此忘记分号会使随后的方法减速无效，并在MSCV编译器输出中引起奇怪的错误。

无法访问派生类中的基类方法

2 个答案: