Can't figure out if I'm inputting arguments incorrectly or if there's something wrong with my code

Question

So, I barely started learning about linked lists, and I made a a function that inserts a head into the linked list. The problem I'm having trouble figuring out is if I'm entering in the arguments incorrectly, or if my code has some errors.

node struct:

template<typename T>
struct node
{
public:
    node(node* next = nullptr, const T& item = T());

    template<typename U>
    friend ostream& operator <<(ostream& outs, const node<U> &print_me);

    T _item;    //crate
    node* next; //label
};

insert_head function:

node<T>* insert_head(node<T> *&head, const T& insert_this)
{
    //create new dynamic variable
    node<T>* temp = new node<T>;    //IT SHOWS THAT THE ERROR OCCURS HERE

    //temp takes in the insert_this item
    temp->_item = insert_this;
    //temp points to the head so it doesn't lose the location
    temp->next = head;
    //head points back to temp
    head = temp;

    return head;    //returns back the head of the list
}

Main:

{
    node<int>* head_ptr = nullptr;

    for(node<int>* nPtr = head_ptr; nPtr != nullptr; nPtr = nPtr->next)
    {
        insert_head(head_ptr, 7); //insert integer 5 into the head
        PrintList(head_ptr);  //print the linked list
    }

return 0;
}

Error: undefined reference to 'node::node(node*, int const&)'

My node methods are defined in the same header file as the node struct because it is templated. The insert_head function is defined in another header file that I will use as a general linked list function. — Rich, Oct 16 '19 at 08:51
Please create a proper [mcve] to show us, so we know exactly what is being done and what happens. — Some programmer dude, Oct 16 '19 at 08:53
How does you implementation of `node` constructor look like? — Yksisarvinen, Oct 16 '19 at 08:56
In the class you *declare* the constructor. Then you need to *define* (implement) it as well. If there's no definition (implementation) then you will get an error like the one you have. — Some programmer dude, Oct 16 '19 at 09:37

Can't figure out if I'm inputting arguments incorrectly or if there's something wrong with my code

0 Answers0