Thread: Doubly circular linked list

I'm building trivial doubly circular linked list and I have partially written insert at front function, so far I have the case when the list is empty (head is NULL), but why does it output 10 if I do

Code:

cout << head->data << endl;

more than once if I only stored one node w/ data: 1000? It shouldnt' matter how many times I want to print out the data member...

Code:

#include <iostream>

using namespace std;

struct doubly_cll//doubly circular linked list obj
{
    int data;
    doubly_cll* next;
    doubly_cll* back;
};

doubly_cll* insert(doubly_cll** head, int d)//insert new node w/ data d (duplicates allowed)
{
    doubly_cll newNode;//NB: If I used: doubly_cll* newNode = new doubly_cll; then to access a member can be: newNode->data OR (*newNode).data
    newNode.data = d;//NB: or newNode->data = d if I had dynamically alloced memory (used a ptr var to a doubly_cll)
    
    if ( *head == NULL )//case 1: empty list
    {
        cout << "Empty list..." << endl;
        newNode.next = &newNode; newNode.back = &newNode;
        *head = &newNode;
        return *head;//in main, to update head ptr: head = insert(head, 87);
    }
}

int main()
{
   doubly_cll* head = NULL;
    head = insert(&head, 1000);
    cout << head->data << endl;
    cout << head->data << endl;
    cout << head->data << endl;
    cout << head->data << endl;
    cout << head->data << endl;
   return 0;
}

The reason I'm printing it out so many times is b/c I tried to print w. a do-while loop, and I noticed it outputted 10 even though I only stored a node w/ data member of value 1000.

Code:

 doubly_cll* cur = head;
cout << (*cur).data << endl;
    do
    {
        cout << "cur node: " << (*cur).data << ", ";//<=> cur->data ('->' just syntactic sugar)
        cur = (*cur).next;//cur is a ptr, member 'next' is a ptr so why doesn't this work? a ptr cannot hold a member?
    }
    while( cur != head );//stop when we pt back to head node (no NULL so this is stop condition)