#include <stdio.h>
#include <stdlib.h>
 
// Define structure for node
struct Node {
    int data;
    struct Node *next;
};
 
int main() {
    struct Node *head = NULL, *temp = NULL, *newNode = NULL;
    int choice = 1;
 
    while (choice) {
        // Dynamically allocate memory for new node
        newNode = (struct Node*) malloc(sizeof(struct Node));
        if (newNode == NULL) {
            printf("Memory allocation failed!\n");
            return 1;
        }
 
        printf("Enter data for node: ");
        scanf("%d", &newNode->data);
        newNode->next = NULL;
 
        // First node creation
        if (head == NULL)
            head = temp = newNode;
        else {
            temp->next = newNode;  // Link new node
            temp = newNode;        // Move temp to last node
        }
 
        printf("Do you want to add another node? (1-Yes / 0-No): ");
        scanf("%d", &choice);
    }
 
    // Display the linked list
    printf("\nLinked List Elements:\n");
    temp = head;
    while (temp != NULL) {
        printf("%d -> ", temp->data);
        temp = temp->next;
    }
    printf("NULL\n");
 
    // Free allocated memory
    temp = head;
    struct Node *nextNode;
    while (temp != NULL) {
        nextNode = temp->next;
        free(temp);
        temp = nextNode;
    }
 
    return 0;
}

#include <stdio.h>
#include <stdlib.h>
 
struct Node {
    int data;
    struct Node *next;
};
 
// Function to display linked list
void display(struct Node *head) {
    struct Node *temp = head;
    printf("\nLinked List: ");
    while (temp != NULL) {
        printf("%d -> ", temp->data);
        temp = temp->next;
    }
    printf("NULL\n");
}
 
// Function to insert at beginning
struct Node* insertAtBeginning(struct Node *head, int value) {
    struct Node *newNode = (struct Node*) malloc(sizeof(struct Node));
    newNode->data = value;
    newNode->next = head;
    return newNode;
}
 
// Function to insert at end
struct Node* insertAtEnd(struct Node *head, int value) {
    struct Node *newNode = (struct Node*) malloc(sizeof(struct Node));
    newNode->data = value;
    newNode->next = NULL;
 
    if (head == NULL)
        return newNode;
 
    struct Node *temp = head;
    while (temp->next != NULL)
        temp = temp->next;
    temp->next = newNode;
    return head;
}
 
// Function to insert at specific position
struct Node* insertAtPosition(struct Node *head, int value, int pos) {
    struct Node *newNode = (struct Node*) malloc(sizeof(struct Node));
    newNode->data = value;
 
    if (pos == 1) {  // Insert at beginning
        newNode->next = head;
        return newNode;
    }
 
    struct Node *temp = head;
    for (int i = 1; i < pos - 1 && temp != NULL; i++)
        temp = temp->next;
 
    if (temp == NULL) {
        printf("Position out of range!\n");
        free(newNode);
        return head;
    }
 
    newNode->next = temp->next;
    temp->next = newNode;
    return head;
}
 
int main() {
    struct Node *head = NULL;
    int choice, value, pos;
 
    while (1) {
        printf("\n=== Linked List Menu ===\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 value to insert: ");
                scanf("%d", &value);
                head = insertAtBeginning(head, value);
                break;
            case 2:
                printf("Enter value to insert: ");
                scanf("%d", &value);
                head = insertAtEnd(head, value);
                break;
            case 3:
                printf("Enter value to insert: ");
                scanf("%d", &value);
                printf("Enter position: ");
                scanf("%d", &pos);
                head = insertAtPosition(head, value, pos);
                break;
            case 4:
                display(head);
                break;
            case 5:
                printf("Exiting...\n");
                exit(0);
            default:
                printf("Invalid choice! Try again.\n");
        }
    }
 
    return 0;
}