#include <stdio.h>
struct Node {
    int data;
    struct Node *next;
    struct Node *prev;
};
struct Node *head;
struct Node* GetNewNode(int x){

    struct Node *newNode = (struct Node*)malloc(sizeof(struct Node));
    newNode->data=x;
    newNode->prev=NULL;
    newNode->next=NULL;
    return newNode;
}
void InsertAtHead(int x){

    struct Node *newNode = GetNewNode(x);
    if(head == NULL){
        head = newNode;
        return;
    }
    head->prev = newNode;
    newNode->next = head;
    head = newNode;

}

void insertAtTail(int x){
    struct Node* last = head;
    struct Node *newNode = GetNewNode(x);
    if(head == NULL){
        head = newNode;
        return;
    }
    newNode->next = NULL;
    while(last->next != NULL){
        last = last->next;
   }
   last->next=newNode;
   newNode->prev=last;


}
void insertAfter(int loc, int x){
    struct Node *temp=head;

    for(int i=0;i<loc;i++){
        temp = temp->next;
    }

    struct Node* prevNode = temp;

    struct Node *newNode = GetNewNode(x);
    newNode->next = prevNode->next;
    prevNode->next=newNode;
    newNode->prev=prevNode;
      if (newNode->next != NULL){
        newNode->next->prev = newNode;
      }
        printf("%d", *(newNode->prev));
}

void Print(){
    struct Node *temp = head;
    while(temp != NULL){
        printf("%d ", temp->data);
        temp = temp->next;
    }
}
void RevPrint(){
    struct Node *temp = head;
    while(temp->next != NULL){
        temp = temp->next;
    }
    while(temp != NULL){
        printf("%d ", temp->data);
        temp = temp->prev;
    }
}


int main()
{
    head = NULL;
    InsertAtHead(2); Print(); RevPrint();
    printf("\n");
    InsertAtHead(4); Print(); RevPrint();
    printf("\n");
    InsertAtHead(6); Print(); RevPrint();
    printf("\n");
    insertAtTail(5); Print(); RevPrint();
    printf("\n");
    insertAfter(1, 55 ); Print(); RevPrint();
}