// -------------------------------------------------------------------------
// System Headers
// -------------------------------------------------------------------------

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

// -------------------------------------------------------------------------
// Typedefs
// -------------------------------------------------------------------------

typedef struct _Node
{
   struct _Node *mNext;
   int mValue;

} Node;

// -------------------------------------------------------------------------
// freeList - Free the linked list starting with 'head'
// -------------------------------------------------------------------------

static void freeList(Node *head)
{
   Node *current = head;

   while(current)
   {
      Node *tmp = current->mNext;

      printf("freeing: [%p]\n", current);

      free(current);

      current = tmp;
   }
}

// -------------------------------------------------------------------------
// makeNode - Dynamically allocate and return a Node with value 'value'
// -------------------------------------------------------------------------

static Node *makeNode(int value)
{
   size_t size = sizeof(Node);
   Node   *ptr = malloc(size);

   if(!ptr)
   {
      printf(
         "[%s | %d] - Could not allocate: %lu bytes\n",
         __FILE__, __LINE__, size
      );

      exit(1);
   }

   printf("allocated: [%p]\n", ptr);

   ptr->mValue = value;
   ptr->mNext  = NULL;

   return(ptr);
}

// -------------------------------------------------------------------------
// makeList - Create and return a linked list of Nodes
// -------------------------------------------------------------------------

static Node *makeList()
{
   Node *head    = NULL;
   Node *current = NULL;
   int  i        = 0;

   while(i <= 10)
   {
      Node *theNode = makeNode(i++);

      if(!head)
      {
         current = head = theNode;
      }
      else
      {
         current->mNext = theNode;
         current        = current->mNext;
      }
   }

   return(head);
}

// -------------------------------------------------------------------------
// reverse - Reverse the list starting with 'head', return the new head
//           of the list.
// -------------------------------------------------------------------------

static Node *reverseList(Node *head)
{
   Node *current = NULL;
   Node *ptr     = head;

   while(ptr)
   {
      Node *next = ptr->mNext;

      ptr->mNext = current;
      current    = ptr;
      
      ptr = next;
   }

   return(current);
}

// -------------------------------------------------------------------------
// dumpList - Output the linked list's contents to the console
// -------------------------------------------------------------------------

static void dumpList(Node *head)
{
   Node *ptr = head;

   while(ptr)
   {
      printf("[%p] => %d\n", ptr, ptr->mValue);
      ptr = ptr->mNext;
   }
}

// -------------------------------------------------------------------------
// main
// -------------------------------------------------------------------------

int main()
{
   Node *list = makeList();

   printf("\n");

   dumpList(list);

   printf("\n");

   Node *reversed = reverseList(list);

   dumpList(reversed);

   printf("\n");

   freeList(reversed);

   return(0);
}