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Question

所以在完成一本介绍性的书之后,我正试着用一些C++,而且我已经陷入了困境.我已经创建了一个对象矢量,每个对象都有一个SFML圆对象作为成员,我希望main()去绘制这些圆.调用向量theBoard,但是当我尝试访问它时,我收到以下错误消息:

error: request for member 'theBoard' in 'GameBoard', which is of non-class type 'Board*'
error: 'theBoard' was not declared in this scope

我是新手(来自两年的Python),所以我确定我在某个地方犯了一个错误.以下是电路板创建的相关代码:

class Board
{
public:
    //These are the member functions.
    Board();
    ~Board();
    vector<Space*> CreateBoard();
    //This will be the game board.
    vector<Space*> theBoard;
    //These clusters represent the waiting areas for pieces not yet in the game.
    vector<Space*> Cluster1;
    vector<Space*> Cluster2;
    vector<Space*> Cluster3;
private:
    //These integers represent the number of spaces on each row, starting at the top     (which is row [0])
    vector<int> RowNums;
};

Board::Board()
{
    //Fill in RowNums with the right values.
    RowNums.push_back(1);
    RowNums.push_back(17);
    RowNums.push_back(2);
    RowNums.push_back(17);
    RowNums.push_back(1);
    RowNums.push_back(1);
    RowNums.push_back(5);
    RowNums.push_back(2);
    RowNums.push_back(7);
    RowNums.push_back(2);
    RowNums.push_back(11);
    RowNums.push_back(3);
    RowNums.push_back(17);
    RowNums.push_back(4);
    RowNums.push_back(17);
    //Then, create the board.
    theBoard = CreateBoard();
}

CreateBoard()是一个非常非常长的函数,它返回一个指向Space对象的指针向量.我怀疑这里有一个问题,因为当我尝试访问main()中的Space对象的圆圈成员时,我得到的唯一错误信息.在我看来,好像我已theBoard在相关范围内声明,即作为Board类的数据成员.

我的main()函数,如果它很重要:

int main()
{
    //This sets up the display window.
    sf::RenderWindow App(sf::VideoMode(1200, 900, 32), "Malefiz");

    //This creates the board on the heap, and a pointer to it.
    Board* GameBoard = new Board();

    cout << "Board made.";

    //This is the game loop.
    while(App.IsOpened())
    {
        //This is used to poll events.
        sf::Event Event;
        while(App.GetEvent(Event))
        {
            //This closes the window.
            if(Event.Type == sf::Event::Closed)
            {
                App.Close();
            }
        }

        //This gets the time since the last frame.
        //float ElapsedTime = App.GetFrameTime();

        //This fills the window with black.
        App.Clear(sf::Color(200, 200, 125));
        //This draws the places into the window.
        for(int i = 0; i < GameBoard.theBoard.size(); ++i)
        {
            App.Draw(GameBoard.*theBoard[i].m_Circle);
        }
        //This displays the window.
        App.Display();
    }

    return EXIT_SUCCESS;
}

Answer 1

在你的main()功能中,GameBoard是一个Board *,而不是一个Board.因此,要访问成员,您需要使用->而不是..例如:

GameBoard->theBoard.size()

[ 有些人(我是其中之一)喜欢用前导p或ptr前缀命名他们的指针变量,以便明确地明白这种烦恼.]