#include <stdio.h>
#include <stdlib.h>
 
// Structure definition
struct Node {
    int data;
    struct Node *prev;
    struct Node *next;
};
 
// Function to create a new node
struct Node* createNode(int data) {
    struct Node *newNode = (struct Node*)malloc(sizeof(struct Node));
    newNode->data = data;
    newNode->prev = NULL;
    newNode->next = NULL;
    return newNode;
}
 
// Function to insert at end (for setup)
struct Node* insertAtEnd(struct Node *head, int data) {
    struct Node *newNode = createNode(data);
    if (head == NULL)
        return newNode;
 
    struct Node *temp = head;
    while (temp->next != NULL)
        temp = temp->next;
 
    temp->next = newNode;
    newNode->prev = temp;
    return head;
}
 
// Function to display list
void displayList(struct Node *head) {
    struct Node *temp = head;
    printf("\nDoubly Linked List: ");
    while (temp != NULL) {
        printf("%d <-> ", temp->data);
        temp = temp->next;
    }
    printf("NULL\n");
}
 
// Function to delete from beginning
struct Node* deleteFromBeginning(struct Node *head) {
    if (head == NULL) {
        printf("\nList is empty.\n");
        return NULL;
    }
    struct Node *temp = head;
    head = head->next;
    if (head != NULL)
        head->prev = NULL;
 
    printf("\nDeleted node: %d\n", temp->data);
    free(temp);
    return head;
}
 
// Function to delete from end
struct Node* deleteFromEnd(struct Node *head) {
    if (head == NULL) {
        printf("\nList is empty.\n");
        return NULL;
    }
 
    struct Node *temp = head;
    while (temp->next != NULL)
        temp = temp->next;
 
    printf("\nDeleted node: %d\n", temp->data);
 
    if (temp->prev != NULL)
        temp->prev->next = NULL;
    else
        head = NULL;
 
    free(temp);
    return head;
}
 
// Function to delete from specific position
struct Node* deleteFromPosition(struct Node *head, int pos) {
    if (head == NULL) {
        printf("\nList is empty.\n");
        return NULL;
    }
 
    struct Node *temp = head;
    int i;
    if (pos == 1)
        return deleteFromBeginning(head);
 
    for (i = 1; i < pos && temp != NULL; i++)
        temp = temp->next;
 
    if (temp == NULL) {
        printf("\nPosition out of range!\n");
        return head;
    }
 
    printf("\nDeleted node: %d\n", temp->data);
 
    if (temp->prev != NULL)
        temp->prev->next = temp->next;
 
    if (temp->next != NULL)
        temp->next->prev = temp->prev;
 
    free(temp);
    return head;
}
 
int main() {
    struct Node *head = NULL;
    int n, data, choice, pos, i;
 
    printf("Enter number of initial nodes: ");
    scanf("%d", &n);
 
    for (i = 1; i <= n; i++) {
        printf("Enter data for node %d: ", i);
        scanf("%d", &data);
        head = insertAtEnd(head, data);
    }
 
    displayList(head);
 
    while (1) {
        printf("\n--- MENU ---\n");
        printf("1. Delete from Beginning\n");
        printf("2. Delete from End\n");
        printf("3. Delete from Position\n");
        printf("4. Display List\n");
        printf("5. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);
 
        switch (choice) {
            case 1: head = deleteFromBeginning(head); break;
            case 2: head = deleteFromEnd(head); break;
            case 3:
                printf("Enter position to delete: ");
                scanf("%d", &pos);
                head = deleteFromPosition(head, pos);
                break;
            case 4: displayList(head); break;
            case 5: exit(0);
            default: printf("Invalid choice!\n");
        }
    }
 
    return 0;
}