Указатели и динамически размещаемые массивы; EXC_BAD_ACCESS (код = EXC_I386_GPFLT)

Question

Это мой конструктор, который должен "динамически распределять массивы frontGuards и tailGuards, создавать специальные объекты SNode * в качестве защитников, t ie все объекты SNode вместе (как prev-next, так и up-down)":

// SkipList constructor
SkipList::SkipList(int Depth) {
    // The depth of the SkipList is given in the constructor,
    // so frontGuards and rearGuards will have to be dynamically
    // allocated arrays, using frontGuards = new SNode*[depth];
    // where for the level L0, the frontGuard will be frontGuards[0]
    // and rear guard frontGuards[0]

    FrontGuards = new SNode* [Depth];
    RearGuards = new SNode* [Depth];

    FrontGuards[0] -> Data = INT_MIN;
    RearGuards[0] -> Data = INT_MAX;
    FrontGuards[0] -> Next = RearGuards[0];
    RearGuards[0] -> Prev = FrontGuards[0];
    FrontGuards[0] -> Prev = nullptr;
    RearGuards[0] -> Next = nullptr;
    FrontGuards[0] -> UpLevel = nullptr;
    FrontGuards[0] -> DownLevel = nullptr;
    RearGuards[0] -> UpLevel = nullptr;
    RearGuards[0] -> DownLevel = nullptr;
}

Это мой .h:

private:
    // private SNode
    // defined in .cpp as SkipList::SNode::SNode(int Data) ...
    struct SNode {
        // SNode stores int as data
        explicit SNode(int Data);
        // data for SNode
        int Data;
        // link to Next SNode
        SNode *Next;
        // link to Prev SNode
        SNode *Prev;
        // link to up one level
        SNode *UpLevel;
        // link to down one level
        SNode *DownLevel;
    };

    using Snode = struct Snode;

    // Depth of SkipList
    int Depth;

    // array of Depth SNode* objects as FrontGuards linking levels
    SNode **FrontGuards;

    // array of Depth SNode* objects as RearGuards linking levels
    SNode **RearGuards;
}

Я получаю сообщение об ошибке: EXC_BAD_ACCESS (code = EXC_I386_GPFLT) для строки "FrontGuards [0] -> Data = INT_MIN;" и я не уверен почему.