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

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

void print_linked_list(struct node *head) {
  struct node *temp = head;
  if (temp == NULL) {
	printf("[X]\n");
	return;
  }
  while (temp!=NULL) {  
	printf("%d -> ", temp->data);
	temp = temp->next;
  }
  printf("[X]\n");  
}

void search_linked_list(struct node* head, int data) {
  struct node* temp;
  int pos = 0;
  temp = head;
  while(temp!=NULL) {
	if(temp->data==data)
	  printf("Found %d at position: %d\n", data, pos);
    temp = temp->next;
	pos ++;
  }
}

struct node* insert_linked_list(struct node* head, int i, int index) {
  // test head == NULL
  // if index > length of linked list, return -1

  struct node* temp, *cur;
  temp = (struct node *) malloc(sizeof(struct node));
  temp->data = i;
  if(index == 0) {
	temp->next = head;
	head = temp;
  } else {
	cur = head;
	while (index--) {
	  cur = cur->next;
	}
	temp->next = cur->next;
	cur->next = temp;
  }
  return head;
}


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

  /*
   * Task1: Create linked list from user input
   */
  
  for(num=0; num<5; num++){
	printf("enter node data: ");
	scanf("%d", &value);
	temp = (struct node *) malloc(sizeof(struct node));
	temp->data = value;
	temp->next = head;
	head = temp;
  }

  /*
   * Task2: Print linked list 
   */
  print_linked_list(head);
  
  /*
   * Task4: Search element
   */

  printf("Search: \n");
  search_linked_list(head, 2);


  /*
   * Task5: Insert element
   */
  printf("Insert: \n");
  head = insert_linked_list(head, 10, 2);
  print_linked_list(head);

  
  
  /*
   * Task3: Free linked list space
   */

  temp = head;
  while (head->next!=NULL) {
	temp = head;
	head = head->next;
	free(temp);
	print_linked_list(head);
  }
  free(head);   // free will not change value of head
  head = NULL;  // try remove this line
  print_linked_list(head);  

  return 0;
}