c++ - "bad_alloc"方法调用时抛出异常

Question

我四处寻找这个问题的解决方案，但找不到，所以我只好问问。我的程序是一个迷宫游戏，其中包含许多不同的房间，每个房间都使用指针链接到一个或多个相邻的房间。玩家从一个房间导航到另一个房间，直到找到导出。

当程序到达我的 Turn() 函数中的这一行时，对 getName() 的调用将引发“bad_alloc”异常:

cout << "You are currently in " << current->getName()
//that's not the entire line but it's the important bit

getName() 所做的只是将房间名称作为字符串返回。 current 是 Room* 类型的指针，指向用户当前所在的房间。我猜这个指针就是问题所在，但很明显在 main() 中定义:

int main()
{
    //first I create a Maze object to hold important variables, and then the nineteen rooms
    Maze maze = Maze();
    Room room1 = Room("Room A");
    Room room2 = Room("Room B");
    Room room3 = Room("Room C");
    //and so on...
    Room empty = Room("");  //used as a placeholder for rooms with less than five adjacent rooms

    //set the rooms adjacent to each room
    room1.SetAdjacent(room2, room3, room4, empty, empty);
    room2.SetAdjacent(room1, room5, room6, empty, empty);
    room3.SetAdjacent(room1, room6, room7, room15, empty);
    //and so on...

    //this explicitly sets the "current" pointer to point to room1:
    maze.SetCurrent(&room1);

    cout << "Welcome to The Maze Game. Can you find your way out?" << endl;
    system("pause");

    do
    {
        maze.Turn();
        if (maze.GetWinStatus() == true)
        {
            cout << "You have reached the exit! Congratulations!" << endl;
        }
        system("pause");
    } while (maze.GetWinStatus() == false);  //if the player hasn't moved to the exit, then it loops round for another turn

    return 0;
}

所以我不明白为什么它会抛出这个异常。如果您想查看任何其他代码，请询问，我很乐意将其张贴在这里。

编辑 2:这是整个 Room 类，按照要求:

class Room
{
private:
    string roomName;
    Room* adjacentRooms[5];
public:
    Room(string name);
    string getName();
    void SetAdjacent(Room adj1, Room adj2, Room adj3, Room adj4, Room adj5);
    Room* GetAdjacent(int room);
};

Room::Room(string name)
{
    roomName = name;
}

string Room::getName()  //this is the bit that makes it crash
{
    return roomName;
}

void Room::SetAdjacent(Room adj1, Room adj2, Room adj3, Room adj4, Room adj5)
{   //sets which rooms are adjacent to the room this function is called from
    adjacentRooms[0] = &adj1;
    adjacentRooms[1] = &adj2;
    adjacentRooms[2] = &adj3;
    adjacentRooms[3] = &adj4;
    adjacentRooms[4] = &adj5;
}

Room* Room::GetAdjacent(int room)
{   //returns one of the five adjacent rooms. Numbers 1-5 are used as inputs for user convenience
    return adjacentRooms[room - 1];   //the number is lowered by 1 to get the right room in the array
}

Answer 1

您的问题是您的 SetAdjacent 方法:

void SetAdjacent(Room adj1, Room adj2, Room adj3, Room adj4, Room adj5);

应通过引用获取其参数:

void SetAdjacent(Room& adj1, Room& adj2, Room& adj3, Room& adj4, Room& adj5);

发生的事情是您正在获取函数返回后超出范围的临时地址。对该内存的后续访问是未定义的行为。