InsertionAtHead.DLL

#include <stdlib.h>
#include <iostream>
#include <vector>
using namespace std;

struct node {
    int data;
    node *next;
    node *back;

    node (int data1, node *next1,node* back1) {
        data=data1;
        next=next1;
        back=back1;
    }

    node (int data1) {
        data=data1;
        next=nullptr;
        back=nullptr;
    }
};

void printNodes(node *head) {
    while (head!=NULL) {
        cout << head->data << endl;
        head=head->next;
    }
}

node *convertarr2LL (vector <int> &arr) {
    node *head=new node (arr[0]);
    node *prev=head;
    for (int i=1;i<arr.size();i++) {
        node *temp=new node (arr[i],nullptr,prev);
        prev->next=temp;
        prev=temp;
    }
    return head;
}

node *InsertionAtHead (node *head, int value) {
    node *newnode= new node (value,head,NULL);
    head->back=newnode;
    return newnode;
}

int main () {
    vector <int> arr = {1,2,3,4,5};
    node *head = convertarr2LL(arr);
    head= InsertionAtHead(head,0);
    printNodes(head);
}