labQuasetion

#include"iostream"
#include"string"
using namespace std;
struct node
{
    int data;
    node* prev;
    node* next;
};
void insert(node*& head, node*& tail, int item)
{
    node* newNode = new node;
    newNode->data = item;
    newNode->next = NULL;
    newNode->prev = NULL;
    if (head == NULL)
    {
        head = tail = newNode;
        return;
    }
    else
    {
        newNode->next = head;
        head->prev = newNode;
        head = newNode;
    }
}
void merge(node*& head, node*& tail, node*& head1)
{
    node* temp = new node;
    temp = tail;
    if (head == NULL)
    {
        cout << "Empty\n";
        return;
    }
    else
    {
        if (temp->next == NULL)
        {
            temp->next = head1;
            head1->prev = temp;
        }
    }
}
void dis(node*& head, node*& tail1)
{
    node* temp = new node;
    temp = tail1;
    if (head == NULL)
    {
        cout << "Empty\n";
        return;
    }
    else
    {
        while (temp != NULL)
        {
            cout << "--| " << temp->data << endl;
            temp = temp->prev;
        }
    }
}
int main()
{
    node* head, * tail,*head1,*tail1;
    head = tail = head1 = tail1 = NULL;
    int i, item;
    for (i = 0; i < 4; i++)
    {
        cout << "Data is : ";
        cin >> item;
        insert(head, tail, item);
    }
    for (i = 0; i < 4; i++)
    {
        cout << "Data is : ";
        cin >> item;
        insert(head1, tail1, item);
    }
    merge(head, tail, head1);
    dis(head, tail1);
}