#include <stdio.h>
#include <stdlib.h>
 
// Structure for a node
struct Node {
    int data;
    struct Node *next;
};
 
// Function to create linked list
struct Node* createList(int n) {
    struct Node *head = NULL, *temp, *newNode;
    int data, i;
 
    for (i = 1; i <= n; i++) {
        newNode = (struct Node*)malloc(sizeof(struct Node));
        if (newNode == NULL) {
            printf("Memory allocation failed!\n");
            exit(0);
        }
 
        printf("Enter data for node %d: ", i);
        scanf("%d", &data);
        newNode->data = data;
        newNode->next = NULL;
 
        if (head == NULL)
            head = newNode;
        else
            temp->next = newNode;
 
        temp = newNode;
    }
    return head;
}
 
// Function to display linked list
void displayList(struct Node *head) {
    struct Node *temp = head;
    if (head == NULL) {
        printf("\nList is empty.\n");
        return;
    }
 
    printf("\nLinked List: ");
    while (temp != NULL) {
        printf("%d -> ", temp->data);
        temp = temp->next;
    }
    printf("NULL\n");
}
 
// Function to reverse linked list
struct Node* reverseList(struct Node *head) {
    struct Node *prev = NULL, *current = head, *next = NULL;
 
    while (current != NULL) {
        next = current->next;   // store next node
        current->next = prev;   // reverse pointer
        prev = current;         // move prev ahead
        current = next;         // move current ahead
    }
    head = prev;                // update head
    return head;
}
 
int main() {
    struct Node *head = NULL;
    int n;
 
    printf("Enter number of nodes: ");
    scanf("%d", &n);
 
    head = createList(n);
 
    printf("\nOriginal Linked List:");
    displayList(head);
 
    head = reverseList(head);
 
    printf("\nReversed Linked List:");
    displayList(head);
 
    return 0;
}