字符串數據成員的錯誤指針 - 獲取訪問違規

Question

編輯：已解決：我只是沒有初始化currLevel，導致數據成員上的錯誤指針。

我正在使用SDL編寫一個簡單的遊戲。遊戲以解決迷宮爲中心。每個迷宮都有一個對應的文本文件，我的程序可以讀取並相應地設置一個MazeMap對象。

我測試了它的隔離，它似乎是初始化罰款。但是，當我創建了我的引擎類並在其中創建了我的MazeMap對象時，我得到了此訪問衝突，並且在調試器中將迷宮的名稱標記爲不正確的指針。下面是代碼：

MazeMap.h：

class MazeMap{ 
public: 
    MazeMap() {} 
    ~MazeMap(); 

    /*Initializes all the data members using a text file of the following format: 
    1    |-First line is the level number of the maze 
    level.png  |-Background image for the level 
    Level Name  |-Name of the level 
    4x4    |-Number of rows x cols 
    S.XX   |-The actual map: 
    X...   | -S: start location 
    XXX.   | -X: Wall, .: passable ground 
    E...   | -E: end of the level*/ 
    void init(std::string level_file); 

    //Prints the maze to std::cout 
    void print() const; 

    //Calls uti::apply_surface() on all the surfaces to prepare them for blitting 
    // Surfaces are created for each tile. 
    // Will be called in Engine::render() 
    void drawMaze(SDL_Surface *screen) const; 

private: 
    std::string       MazeName; //THE CULPRIT! 
    int         level, 
             rows, 
             cols; 
    std::vector< std::vector<Tile> > tiles; 
    SDL_Surface*      background; 

    //Used in init() to get level, rows, cols, and MazeName, 
    // as well as initialize the background image. 
    void initMapInfo(std::fstream& map_in); 

    //Used in init() to convert the characters in the text file 
    // to tiles for the tile vector. 
    Tile convert_char_to_tile(char t) const; 

    //Used in print() to convert the tiles back to chars for 
    // printing. 
    char convert_tile_to_char(Tile t) const; 
}; 

的initMapInfo功能在運行時錯誤是發生：

void MazeMap::initMapInfo(std::fstream& map_in){ 
    char x; 
    std::string holder; 

     //First line: get level number 
    std::getline(map_in, holder); 
    level = uti::string_to_int(holder); 

    //Second line: get background image file name 
    std::getline(map_in, holder); 
    background = uti::load_image(holder); 

    //Third line: get name of the level 
    std::getline(map_in, MazeName); //THIS LINE IS FAILING 

    //Fourth line: get rows and cols 
    std::getline(map_in, holder); 
    std::stringstream s(holder); 
    s >> rows >> x >> cols; 
} 

引擎類：

class Engine{ 
public: 
    Engine(); 
    void run(); 
private: 
    SDL_Surface *screen; 
    GameState  currentState; 
    int   currLevel; 
    MazeMap  levels[NUM_LEVELS]; 
    Player   player; 

    //Initializes the screen and sets the caption. 
    void initSDL(); 

    /******************************************************/ 
    /* Primary functions to be used in the main game loop */ 

    //First, input from the player will be taken 
    void processInput(); 
    //Based on the user input, various game world elements will be updated. 
    void update(); 
    //Based on what was updated, the screen will be redrawn accordingly. 
    void render(); 
    ///////////////////////////////////////////////////////// 
}; 

運行（）功能：

void Engine::run(){ 

    bool play = true; 

    MazeMap *curr = &levels[currLevel]; 
    curr->init(TEST_MAZE); 
    curr->drawMaze(screen); 

    while(play){ 
    } 
} 

任何幫助表示讚賞。我意識到這裏有很多代碼，爲此我表示歉意。我只是想徹底。謝謝。

Answer 1

@Slims找到了癥結自己：

解決：我只是不初始化currLevel，造成數據成員就壞指針？