#include <stdio.h>

typedef struct Node
{
    int data;
    struct Node *next;
} Node;

// case 3
Node *delEle(Node *head, int data)
{
    if (head == NULL)
    {
        printf("Linked list is empty.\n");
        return NULL;
    }
    Node *current = head;
    Node *prev = NULL;
    while (current != NULL && current->data != data)
    {
        prev = current;
        current = current->next;
    }
    if (current == NULL)
    {
        printf("Element not found in the linked list.\n");
        return head;
    }
    if (prev == NULL)
    {
        head = current->next;
    }
    else
    {
        prev->next = current->next;
    }
    free(current);
    printf("Element deleted successfully.\n");
    return head;
}

// case 4
void dispList(Node *head)
{
    if (head == NULL)
    {
        printf("Linked list is empty.\n");
        return;
    }
    Node *current = head;
    printf("Linked list elements: ");
    while (current != NULL)
    {
        printf("%d ", current->data);
        current = current->next;
    }
    printf("\n");
}

int main()
{
    Node *head = NULL;
    int choice, data;
    while (1)
    {
        printf("Choose the Linked List Operation you would like to perform:\n");
        printf("1. Insert element BEFORE another element\n2. Insert element AFTER another element\n3. Delete a given element from the list\n4. Traverse the list\n5. Reverse the list\n6. Sort the list\n7. Delete every alternate node in the list\n7. Insert an element in a sorted list\n");
        scanf("%d", &choice);

        switch (choice)
        {
        case 1:
            printf("Enter the value for the latest element: ");
            scanf("%d", &data);
            printf("Enter the number BEFORE which you would like to insert it: ");
            scanf("%d", &data1);
            insBef(data, data1);
            break;
        case 2:
            printf("Enter the value for the latest element: ");
            scanf("%d", &data);
            printf("Enter the number AFTER which you would like to insert it: ");
            scanf("%d", &data1);
            insAft(data, data1);
            break;
        case 3:
            printf("Enter the element you want to delete: ");
            scanf("%d", &data);
            delEle(data);
            break;
        case 4:
            printf("List traversal");
            dispList(head);
            break;
        case 5:
            printf("The reversed link list is: ");
            revList();
            break;
        case 6:
            printf("The sorted list is: ");
            sortList();
            break;
        case 7:
            printf("The list after deleting every alternate node is:");
            delAltNode();
            break;
        case 8:
            printf("Enter the element you want to insert: ");
            scanf("%d", &data);
            enterSortList(data);
            break;
        }
    }
}