Rearrange the Even-Odd position Nodes of Doubly Linked List

Question

#include <iostream>
#include <cstdio>
#include <cmath>
using namespace std;

struct Node {
    int data;
    Node* next;
    Node* prev;
    Node(int d)
    {
        data = d;
    }
};

Node* insertEnd(Node* head, int data)
{
    Node* node = new Node(data);
    Node* last = head;
    node->next = NULL; // link new node to NULL as it is last node
    if (head == NULL) // if list is empty add in beginning.
    {
        head = node;
        node->prev = NULL;
        return head;
    }
    while (last->next != NULL) // Find the last node
        last = last->next;
    last->next = node; // Add the node after the last node of list
    node->prev = last;
    return head;
}

// This function prints contents of linked list starting from head
void printList(Node* node)
{
    while (node != NULL) {
        cout << node->data << ' ';
        node = node->next;
    }
}

Node* rearrangeList(Node* head)
{
    Node* newN = NULL;
    Node* odd = head;
    Node* even = head->next;
    while (even != NULL) {
        insertEnd(newN, even->data);
        if (even->next == NULL) {
            break;
        }
        even = even->next->next;
    }
    while (odd != NULL) {
        insertEnd(newN, odd->data);
        if (odd->next == NULL) {
            break;
        }
        odd = odd->next->next;
    }
    return newN;
}

int main()
{
    int t;
    cin >> t;
    while (t--) {
        Node* head = NULL;
        int n, m, x, y;
        cin >> n;
        while (n--) {
            cin >> m;
            head = insertEnd(head, m);
        }
        head = rearrangeList(head);
        printList(head);
        cout << endl;
    }
    return 0;
}

In this code we have to arrange the even position nodes in front and odd position nodes at end.

Whenever I try to run it I get a segmentation fault(on Code quotient) (on online gdb it gives no output).

Sample Input

1

7

1 -> 3 -> 5 -> 7 -> 9 -> 11 -> 13

Sample Output

3 7 11 1 5 9 13 Can anyone tell me where I am messing up in this problem .Thanks For the help!