C++链表队列实现和析构函数错误:"Aborted (Core Dumped)"

Question

我正在尝试学习 C++，但我在内存管理和析构函数的概念方面遇到了问题。我尝试使用链表编写队列实现，当我尝试在析构函数方法中删除链表节点(粗体)时收到“已中止(核心已转储)”错误消息。如果有人知道我做错了什么，请告诉我!

这是我的析构方法的代码:

template <class T>
Queue<T>::~Queue(){
  Node<T> *currHead = head;
  while(currHead != NULL){
    Node<T> *nextHead = currHead->next;
    delete currHead;
    currHead = nextHead;
  }
  Node<T> *currTail = tail;
  while(currTail != NULL){
    Node<T> *nextTail = currTail->next;
    delete currTail;
    currTail = nextTail;
  }
}

这里是我完整的链表队列实现以供引用:

template <class T>
class Node{
public:
  T data;
  Node<T> *next=NULL;
};

template <class T>
class Queue{
public:
  Queue();
  ~Queue();
  void push(T);
  T pop();
  int size=0;
  Node<T> *head=NULL;
  Node<T> *tail=NULL;
};

template <class T>
Queue<T>::Queue(){}

template <class T>
Queue<T>::~Queue(){
  Node<T> *currHead = head;
  while(currHead != NULL){
    Node<T> *nextHead = currHead->next;
    delete currHead;
    currHead = nextHead;
  }
  Node<T> *currTail = tail;
  while(currTail != NULL){
    Node<T> *nextTail = currTail->next;
    delete currTail;
    currTail = nextTail;
  }
}

template <class T>
void Queue<T>::push(T data){
  Node<T> *node = new Node<T>;
  node->data = data;
  if(head == NULL){
    head = node;
  }else{
    tail->next = node;
  }
  tail = node;
  size++;
}

template <class T>
T Queue<T>::pop(){
  if(size == 0){
    throw "Empty Queue";
  }else{
    Node<T> *oldHead = head;
    T oldData = oldHead->data;
    head = head->next;
    size--;
    delete oldHead;
    return oldData;
  }
}

编辑:

我也为析构函数尝试了以下定义，但我得到了同样的错误:

template <class T>
Queue<T>::~Queue(){

  while(head != NULL){
    Node<T> *currHead = head;
    head = head->next;
    delete currHead;
  }

  while(tail != NULL){
    Node<T> *currTail = tail;
    tail = tail->next;
    delete currTail;
  }
}

Answer 1

在析构函数的第一部分，您要删除从 head 开始的所有列表项。在析构函数的第二部分中，您尝试使用保留在尾部的指针再次删除最后一个列表项，但它已在第一部分中被删除。