// Pantea Aria

// linked list
// - create_node
// - print_list
// - insert_at_tail
// - delete_first
// - delete_all
// - search_and_delete

#include <stdio.h>
#include <stdlib.h>

struct node {
    int data;
    struct node *next;
};

struct node *create_node(int data, struct node *next);
void print_list(struct node *head);
struct node *insert_at_tail(struct node *head, int data);

struct node *delete_first(struct node *head);
struct node * delete_all(struct node *head);
struct node *search_and_delete(struct node *head, int value);

int main(void) {
    struct node *head = NULL;

    // Print the empty list
    print_list(head);

    printf("Search and delete from empty list\n");
    // Try deleting 99 from an empty list
    head = search_and_delete(head, 1000);
    print_list(head);

    // Build a list that stores 0..9 by inserting at the tail
    for (int i = 0; i < 10; i++) {
        head = insert_at_tail(head, i);
    }
    print_list(head);
    
    printf("delete first '0'\n");
    // Delete first
    head = delete_first(head);
    print_list(head);
    
    //delete_all(head);
   // print_list(head);
    

    printf("Search and delete 4\n");
    // Delete 4 (middle case)
    head = search_and_delete(head, 4);
    print_list(head);

    printf("Search and delete 1000\n");
    // Delete 99 (not found case)
    head = search_and_delete(head, 1000);
    print_list(head);

    printf("Search and delete 9\n");
    // Delete 9 (tail case)
    head = search_and_delete(head, 9);
    print_list(head);

    printf("Search and delete 0\n");
    // Delete 0 (head case)
    head = search_and_delete(head, 0);
    print_list(head);

    // Free all remaining nodes to prevent memory leaks
    head = delete_all(head);

    print_list(head);

    return 0;
}

// TODO: Allocate memory for a new node using malloc.
// TODO: If malloc fails, return NULL.
// TODO: Set new_node->data and new_node->next, then return new_node.
struct node *create_node(int data, struct node *next) {
    // TODO

}

// TODO: Traverse from head to NULL and print each node’s data.
// TODO: Print something like: "list:" then the values on one line.
void print_list(struct node *head) {
    // TODO
  
}

// TODO: Insert a new node (with given data) at the end of the list.
// Cases to handle:
// - Empty list: new node becomes the head.
// - Non-empty list: traverse to last node, then link it to new node.
// Return the (possibly updated) head.
struct node *insert_at_tail(struct node *head, int data) {
    // TODO

}

// TODO: Delete the first node (if it exists) and free it.
// Return the new head pointer.
struct node *delete_first(struct node *head) {
    // TODO

}

// TODO: Free every node in the list.
// Hint: you must save the next pointer before calling free on current.
// issues here
struct node *delete_all(struct node *head) {
    // TODO

          
}

// TODO: Find the first node whose data == value, remove it from the list,
// and free it.
// Cases to handle:
// - Empty list
// - Value not found
// - Deleting head node
// - Deleting middle/tail node
// Return the updated head.
struct node *search_and_delete(struct node *head, int value) {

}