模板链表 Class 的复制构造函数错误：没有匹配函数来调用 'Node<int>::Node()'

Question

我正在尝试为链表创建一个复制构造函数，但我不确定如何修复这个错误，我已经找了好几个小时了。错误是：

no matching function for call to 'Node::Node()'

代码如下：

template <class T>
class Node      //node is the name of class, not specific
{
public:
    T data;     //t data allows for any type of variable
    Node *next;     //pointer to a node

    Node(T Data)    //assign data value
    {
        data = Data;    //makes data = NV parameter
        next = nullptr; //makes next = to nullptr
    }
};

template <class T>
class LinkedList
{
private:
    Node<T> * head, *tail;      //// typedef Node* head // -- head = Node* --   //// typedef Node* nodePtr =  Node* ////
public:
    LinkedList()        //constructor for Linked List
    {
        head =  nullptr;
        tail = nullptr;
    }

    LinkedList(LinkedList& copy)
    {
        head = nullptr;
        tail = nullptr;
        Node<T>* Curr = copy.head;


        while(Curr) //while not at end of list
               {
                   //val = copyHead->data;
                   Node<T>* newCpy = new Node<T>;
                   newCpy->data = Curr->data;
                   newCpy->next = nullptr;

                   if(head == nullptr)
                       {
                           head = tail = newCpy;
                       }
                   else
                       {
                           tail->next = newCpy;
                           tail = newCpy;
                       }

               }

    }
       ~LinkedList()
       {
           while (head)
            {
                Node<T>* tmp = head;
                head = head->next;
                delete(tmp);
            }
            head = nullptr;
       }

Answer 1

class节点没有默认构造函数。它只有以下构造函数

Node(T Data)    //assign data value
{
    data = Data;    //makes data = NV parameter
    next = nullptr; //makes next = to nullptr
}

并且在这个声明中

Node<T>* newCpy = new Node<T>;

使用了不存在的默认构造函数。

至少不是这三个说法

//val = copyHead->data;
Node<T>* newCpy = new Node<T>;
newCpy->data = Curr->data;
newCpy->next = nullptr;

你需要写

//val = copyHead->data;
Node<T>* newCpy = new Node<T>( Curr->data );

注意while循环中的那个

while(Curr)
{
    //...
}

指针Curr没有改变。所以如果 Curr 不是空指针

则循环是无限的

你好像忘了插入这条语句

Curr = Curr->next;

在循环的右大括号之前。

模板链表 Class 的复制构造函数错误：没有匹配函数来调用 'Node<int>::Node()'

Copy Constructor Error With a Template Linked List Class : no matching function for call to 'Node<int>::Node()'

c++

class

copy-constructor

definition

default-constructor