Question

有人可以帮我吗？

我现在有这个问题，无法解决。

不允许使用抽象类类型的对象：纯虚函数没有覆盖程序”

我在下面突出显示了

class State 
{ 
public:
    virtual void Update() = 0;
    virtual void Render();
    virtual void Enter() = 0;
    virtual void Exit() = 0;
    virtual void Resume() = 0;
protected:
    State() {} 
};

class GameState : public State
{
private:
    Level level;
    Level levels[5] = { Level(3), Level(1), Level(1), Level(2), Level(1) };
    const char* levelNames[5] = { "Level1.txt", "Level2.txt", "Level3.txt", "Level4.txt", "Level5.txt" };
    SDL_Texture* tileText;
    SDL_Texture* playerText;
    Player player;
    SDL_Surface* tileSurf;
    SDL_Surface* playerSurf;

    int m_iTickCtr = 0;
    int m_iTickMax = 1; // for animation

public:
    GameState() {}
    void Update(Level& l, Player& p, int& c) ; // Level& level, Player& player, int& c
    void Render(Level& l, Player& p);
    void Enter();
    void Exit();
    void Resume() { cout << "Resuming Game..." << endl; }
    enum sfx { jump, boom, laser };
};

class TitleState : public State
{
public:
    TitleState() {}
    virtual void Update();
    void Render();
    void Enter(); 
    void Exit();
    void Resume() {}
    enum btn { play, exit };
private: 
    vector<Button*> m_vButtons;
};

void TitleState::Update()
{
    /*
    if (Game::Instance()->KeyDown(SDL_SCANCODE_B) == 1)
        Game::Instance()->GetAM()->PlaySound(sfx::boop);
    */
    for (int i = 0; i < (int)m_vButtons.size(); i++)
        m_vButtons[i]->Update();
    // Parse buttons.
    if (m_vButtons[btn::play]->Clicked())
        Game::Instance()->GetFSM()->ChangeState(new GameState()); // here 'GameState' has problems.
    else if (m_vButtons[btn::exit]->Clicked())
        Game::Instance()->DoQuit();
}

Answer 1

在子类GameState中，必须为void Update()创建覆盖函数，该函数在抽象类State中定义为纯虚函数。

也许您认为是这样做的，因为您创建了void Update(Level& l, Player& p, int& c)，但是由于此函数的签名与void Update()不同，因此不会覆盖它。

纯虚函数没有替代器

1 个答案: