#include <stdio.h>
#include <stdlib.h>
 
// Define structure
struct Node {
    int data;
    struct Node *next;
};
 
// Function to display circular linked list
void display(struct Node *head) {
    struct Node *temp = head;
    if (head == NULL) {
        printf("List is empty.\n");
        return;
    }
 
    printf("\nCircular Linked List: ");
    do {
        printf("%d -> ", temp->data);
        temp = temp->next;
    } while (temp != head);
    printf("(back to head)\n");
}
 
// Function to create circular linked list
struct Node* createList(int n) {
    struct Node *head = NULL, *temp, *newNode;
    int data, i;
 
    for (i = 0; i < n; i++) {
        newNode = (struct Node*)malloc(sizeof(struct Node));
        if (newNode == NULL) {
            printf("Memory allocation failed!\n");
            return head;
        }
        printf("Enter data for node %d: ", i + 1);
        scanf("%d", &data);
        newNode->data = data;
        newNode->next = NULL;
 
        if (head == NULL) {
            head = newNode;
            head->next = head;
            temp = head;
        } else {
            temp->next = newNode;
            newNode->next = head;
            temp = newNode;
        }
    }
    return head;
}
 
// Delete node from beginning
struct Node* deleteFromBeginning(struct Node *head) {
    struct Node *temp = head, *last;
 
    if (head == NULL) {
        printf("List is empty.\n");
        return NULL;
    }
 
    // Only one node
    if (head->next == head) {
        free(head);
        return NULL;
    }
 
    // Traverse to last node
    last = head;
    while (last->next != head)
        last = last->next;
 
    // Adjust links
    last->next = head->next;
    head = head->next;
 
    free(temp);
    printf("\nDeleted node from beginning.\n");
    return head;
}
 
// Delete node from end
struct Node* deleteFromEnd(struct Node *head) {
    struct Node *temp = head, *prev;
 
    if (head == NULL) {
        printf("List is empty.\n");
        return NULL;
    }
 
    // Only one node
    if (head->next == head) {
        free(head);
        return NULL;
    }
 
    // Traverse to last node
    while (temp->next != head) {
        prev = temp;
        temp = temp->next;
    }
 
    prev->next = head;
    free(temp);
    printf("\nDeleted node from end.\n");
    return head;
}
 
// Delete node from specific position
struct Node* deleteFromPosition(struct Node *head, int pos) {
    struct Node *temp = head, *prev;
    int i;
 
    if (head == NULL) {
        printf("List is empty.\n");
        return NULL;
    }
 
    // Delete first node
    if (pos == 1)
        return deleteFromBeginning(head);
 
    for (i = 1; i < pos && temp->next != head; i++) {
        prev = temp;
        temp = temp->next;
    }
 
    // Invalid position
    if (temp == head) {
        printf("\nInvalid position!\n");
        return head;
    }
 
    prev->next = temp->next;
    free(temp);
    printf("\nDeleted node at position %d.\n", pos);
    return head;
}
 
// Main function
int main() {
    struct Node *head = NULL;
    int n, choice, pos;
 
    printf("Enter number of nodes: ");
    scanf("%d", &n);
    head = createList(n);
 
    printf("\nInitial List:\n");
    display(head);
 
    do {
        printf("\n----- MENU -----\n");
        printf("1. Delete from Beginning\n");
        printf("2. Delete from End\n");
        printf("3. Delete from Specific 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);
                display(head);
                break;
            case 2:
                head = deleteFromEnd(head);
                display(head);
                break;
            case 3:
                printf("Enter position to delete: ");
                scanf("%d", &pos);
                head = deleteFromPosition(head, pos);
                display(head);
                break;
            case 4:
                display(head);
                break;
            case 5:
                printf("Exiting program.\n");
                break;
            default:
                printf("Invalid choice! Try again.\n");
        }
    } while (choice != 5);
 
    return 0;
}