double_linked_list

#include <iostream>
using namespace std;

struct Node{
    int data;
    struct Node* prev;
    struct Node* next;
};

struct Node* insert(struct Node* head, int data);
struct Node* insertAtBeg(struct Node* head, int data);
struct Node* insertAtPos(struct Node* head, int pos, int data);


int main() {
    
    struct Node* head;
    head = NULL;
    // Why sending head 
    // What does head contains
    // does head contains NULL or what
    //yes head contains NULL which means its not pointing to anything
    //in the first insert it just passed as value
    
    head = insert(head,10);
    head = insertAtBeg(head,1);
    head = insertAtPos(head,2,13);
    
    // head = insert(head,1);
    // head = insertAtBeg(head,10);
    // head = insertAtPos(head,25,2);
    // head = insert(head,56);
    
    
    
    return 0;
}

struct Node* insert(struct Node* head, int data){
    struct Node* temp = new Node();
    temp->prev = NULL;
    temp->next = NULL;
    temp->data = data;
    if(head == NULL){
        head = temp;
        return head;
    }
    Node* temp1 = head;
    while(temp1->next != NULL){
        temp1 = temp1.next;
    }
    temp->prev = temp1;
    temp1->next = temp;
    
    return head;
}

struct Node* insertAtBeg(struct Node* head, int data){
    struct Node* temp = new Node();
    temp->prev = NULL;
    temp->next = NULL;
    temp->data = data;
    if(head == NULL){
        head = temp;
        return head;
    }
    temp->next = head;
    head->prev = temp;
    head = temp;
    
    return head;
}

struct Node* insertAtPos(struct Node* head, int pos, int data){
    struct Node* temp = new Node();
    temp->prev = NULL;
    temp->next = NULL
    temp->data = data;
    if(head == NULL){
        head = temp;
        return head;
    }
    Node* temp1;
    temp1 = head;
    for(int i =1; i<pos-1; ++i){
        temp1 = temp1->next;
    }
    struct Node* temp2;
    temp2 = temp1->next;
    temp->prev = 
}