C Program for Folding a Linked List

#include<stdio.h>
#include<stdlib.h>
struct node			// structure of the node
{
  int data;
  struct node *next;
};
void reverse_list (struct node **head)	//function for reverse list
{
  struct node *prev = NULL, *curr = *head, *next;
  while (curr)
    {
      next = curr->next;
      curr->next = prev;
      prev = curr;
      curr = next;
    }

  *head = prev;
}

void create (struct node **head, int data)	//function for create list
{
  struct node *new_n;
  new_n = (struct node *) malloc (sizeof (struct node));
  new_n->data = data;
  new_n->next = *head;
  *head = new_n;

}

void print (struct node *head)	//function for display list
{
  struct node *ptr = head;
  while (ptr)
    {
      printf ("%d\n", ptr->data);
      ptr = ptr->next;
    }
}

struct node *newNode (int data)
{

  struct node *new_n;
  new_n = (struct node *) malloc (sizeof (struct node));
  new_n->data = data;
  new_n->next = NULL;
  return new_n;
}

void fold (struct node **head)	//final function for fold a linked list
{
  struct node *slow = *head;
  struct node *fast = slow->next;
  struct node *curr;
  while (fast && fast->next)
    {
      slow = slow->next;
      fast = fast->next->next;
    }
  struct node *head1 = *head;
  struct node *head2 = slow->next;
  slow->next = NULL;

  reverse_list (&head2);

  *head = newNode (0);

  curr = *head;
  while (head1 || head2)
    {
      if (head1)
	{
	  curr->next = head1;
	  curr = curr->next;
	  head1 = head1->next;
	}
      if (head2)
	{
	  curr->next = head2;
	  curr = curr->next;
	  head2 = head2->next;
	}
    }
  *head = (*head)->next;
}

int main ()				//main function of the code
{
  struct node *head = NULL;
  int n, k, i;
  int data[100];
  printf ("Enter size of link list :-\n");
  scanf ("%d", &n);
  printf ("Enter data for link list:-\n");
  for (i = 0; i < n; i++) { scanf ("%d", &data[i]); } for (i = n - 1; i >= 0; i--)	//creating Link list
    {
      create (&head, data[i]);
    }
  printf ("Link list data:-");
  print (head);
  fold (&head);
  printf ("Link list data after fold :-");
  print (head);
  return 0;
}

Output :-
Enter size of link list :-
5
Enter data for link list:-
12
4
51
20
68
Link list data:-
12
4
51
20
68
Link list data after fold :-
12
68
4
20
51