C ++：丢失队列中的指针值

I'm making something that needs to work with a queue, enqueue and dequeue. I made a simplified program(So i wont have to work with 12 classes) and it seems im getting the same problem. I have a class that holds an int and a pointer to it, and while im doing the enqueue dequeue rotations i lose the pointers value and i cant solve this. (I also need to make the queue myself so i cant use any libraries) I have the class 'son.cpp':

我正在做一些需要使用队列,入队和出队的东西。我做了一个简化的程序(所以我不必使用12个类),它似乎我得到了同样的问题。我有一个类,它持有一个int和一个指向它的指针,而我正在进行入队出队轮换,我失去了指针值,我无法解决这个问题。 (我还需要自己编队,所以我不能使用任何库)我有类'son.cpp':

son::son() {
    random = 0;
}

void son::set_point() {
    point = &random;
}

son::son(son &other) {
    this->next = other.next;
    this->prev = other.prev;
    this->random = other.random;
}

void son::print_num() {
    std::cout << "Random number is: " << random << std::endl;
}

son.h:

class son {
public:
    int random;
    son* next;
    son* prev;
    int* point;
    son(son &other);
    son();
    void set_point();
    void print_num();
    ~son();
};

sonqueue.h:

class sonqueue{
    son *_head, *_tail;
public:
    sonqueue();
    bool isEmpty();
    son* dequeue();
    void enqueue(son&);
    ~sonqueue();
};

sonqueue.cpp:

sonqueue::sonqueue(){
    _tail = NULL;
    _head = NULL;
}

bool sonqueue::isEmpty() {
    if (_tail == NULL && _head == NULL)
        return true;
    return false;
}

son* sonqueue::dequeue() {
    if (!isEmpty()) {
        std::cerr <<"in queues head random "<< (_tail->point)<<std::endl;
        son *sp = new son(*_head);
        son *temp = sp->prev;
        delete _head;
        _head = temp;
        _head->next = NULL;
        return sp;
    }
    else {
        exit(5);
    }
}

void sonqueue::enqueue(son &ptr) {
    if (!isEmpty()) {
        _tail->prev = &ptr;
        (ptr.next) = _tail;
        _tail = &ptr;
        ptr.prev = NULL;
    }
    else {
        _tail = &ptr;
        _head = &ptr;
        ptr.prev = NULL;
        ptr.next = NULL;
    }
}

sonqueue::~sonqueue(){
    son *point = _tail;
    while (point->next != NULL) {
        son *to_be_del = dequeue();
        delete to_be_del;
    }
}

and the main.cpp:

和main.cpp:

int main() {
    sonqueue *sq = new sonqueue();
    for (int i = 0; i < 3; i++) {
        son *son_to_be = new son();
        son_to_be->random = i;
        son_to_be->set_point();
        sq->enqueue(*son_to_be);
    }
    while (std::cin.get() != (char)27) {
        son *son_obj = sq->dequeue();
        son_obj->print_num();
        sq->enqueue(*son_obj);
    }
    system("PAUSE");
}

I must be missing something because this code works perfectly with ints and such but when i try to do this with pointers i lose that value(As the address changes) How can i implement this so it also carries the pointers value?

我必须遗漏一些东西,因为这段代码完全适用于int等等但是当我尝试使用指针执行此操作时我会丢失该值(因为地址更改)我如何实现它以便它还带有指针值?

EDIT: What i mean is when i try to go over the queue(enqueue-dequeue-enqueue...) I lose the value of point as its not going together with the other data members of the object(I believe because a it pointing to an address it doesnt copy the address)

编辑:我的意思是当我试图越过队列(enqueue-dequeue-enqueue ...)我失去了点的价值,因为它不与对象的其他数据成员一起(我相信因为它指向到一个地址,它不复制地址)

Thanks

1 个解决方案

#1

I'm quite sure that it has to do with copying son-objects within queue-operations. But as you already have a copy constructor in place, extending this with an adaption of point should solve your problem:

我很确定它与在队列操作中复制子对象有关。但是,由于您已经有一个复制构造函数,通过适应点来扩展它应该可以解决您的问题:

son::son(son &other) {
    this->next = other.next;
    this->prev = other.prev;
    this->random = other.random;
    this->point = &this->random;
}

There might be other issues as well, e.g. memory leaks, but that's not your question, right?

可能还有其他问题,例如内存泄漏,但这不是你的问题,对吧?