#include <stdio.h>
#include <stdlib.h>
 
// Structure definition
struct Node {
    int data;
    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->next = NULL;
    return newNode;
}
 
// Function to create a circular linked list
struct Node* createCircularList(int n) {
    struct Node *head = NULL, *temp, *newNode;
    int data, i;
 
    for (i = 1; i <= n; i++) {
        printf("Enter data for node %d: ", i);
        scanf("%d", &data);
        newNode = createNode(data);
 
        if (head == NULL) {
            head = newNode;
            temp = head;
        } else {
            temp->next = newNode;
            temp = newNode;
        }
    }
    temp->next = head; // Make it circular
    return head;
}
 
// Function to display circular linked list
void displayCircularList(struct Node *head) {
    struct Node *temp = head;
    if (head == NULL) {
        printf("\nList is empty.\n");
        return;
    }
    printf("\nCircular Linked List: ");
    do {
        printf("%d -> ", temp->data);
        temp = temp->next;
    } while (temp != head);
    printf("(back to head)\n");
}
 
// Insert at beginning
struct Node* insertAtBeginning(struct Node *head, int data) {
    struct Node *newNode = createNode(data);
    struct Node *temp = head;
 
    if (head == NULL) {
        newNode->next = newNode;
        head = newNode;
        return head;
    }
 
    // Move to last node
    while (temp->next != head)
        temp = temp->next;
 
    temp->next = newNode;
    newNode->next = head;
    head = newNode;
 
    return head;
}
 
// Insert at end
struct Node* insertAtEnd(struct Node *head, int data) {
    struct Node *newNode = createNode(data);
    struct Node *temp = head;
 
    if (head == NULL) {
        newNode->next = newNode;
        head = newNode;
        return head;
    }
 
    while (temp->next != head)
        temp = temp->next;
 
    temp->next = newNode;
    newNode->next = head;
 
    return head;
}
 
// Insert at specific position
struct Node* insertAtPosition(struct Node *head, int data, int pos) {
    struct Node *newNode = createNode(data);
    struct Node *temp = head;
    int i;
 
    if (pos == 1)
        return insertAtBeginning(head, data);
 
    for (i = 1; i < pos - 1 && temp->next != head; i++)
        temp = temp->next;
 
    newNode->next = temp->next;
    temp->next = newNode;
 
    return head;
}
 
int main() {
    struct Node *head = NULL;
    int n, data, pos, choice;
 
    printf("Enter number of nodes: ");
    scanf("%d", &n);
    head = createCircularList(n);
    displayCircularList(head);
 
    do {
        printf("\nMenu:\n");
        printf("1. Insert at Beginning\n");
        printf("2. Insert at End\n");
        printf("3. Insert at Position\n");
        printf("4. Display List\n");
        printf("5. Exit\n");
        printf("Enter your choice: ");
        scanf("%d", &choice);
 
        switch (choice) {
        case 1:
            printf("Enter data to insert: ");
            scanf("%d", &data);
            head = insertAtBeginning(head, data);
            break;
 
        case 2:
            printf("Enter data to insert: ");
            scanf("%d", &data);
            head = insertAtEnd(head, data);
            break;
 
        case 3:
            printf("Enter data and position: ");
            scanf("%d %d", &data, &pos);
            head = insertAtPosition(head, data, pos);
            break;
 
        case 4:
            displayCircularList(head);
            break;
 
        case 5:
            printf("Exiting...\n");
            break;
 
        default:
            printf("Invalid choice!\n");
        }
    } while (choice != 5);
 
    return 0;
}