// Prototypes of auxiliary functions.

void GetNode(int& nodeIndex, MemoryType& storage);
// Returns the index of a free node in nodeIndex.
void FreeNode(int nodeIndex, MemoryType& storage);
// Returns nodeIndex to storage.
void InitializeMemory(int maxItems, MemoryType&);
// Initializes all memory to the free list.

// Define end-of-list symbol.
const int NUL = -1;

struct NodeType
{
  int info;
  int next;
};


// Definitions of the auxillary functions

void InitializeMemory(int maxItems, MemoryType& storage)
{
  for (int index = 1; index < maxItems; index++)
    storage.nodes[index-1].next = index;
  // storage.nodes[maxItems-1] = NUL; 
  storage.nodes[maxItems-1].next = NUL; 
  storage.free = 0;
}

void GetNode(int& nodeIndex, MemoryType& storage)
{
  nodeIndex = storage.free;
  //error:    storage.free = storage.nodes[free].next;
  storage.free = storage.nodes[storage.free].next;
}

void FreeNode(int nodeIndex, MemoryType& storage)
{
  storage.nodes[nodeIndex].next = storage.free;
  storage.free = nodeIndex;
}

//The class constructors for class ListType must allocate the storage
//for the array of records and call InitializeMemory.  For the default
//constructor, we arbitrarily choose an array size of 500.

ListType::ListType(int max)
{
  length = 0;
  maxItems = max;
  storage.nodes = new NodeType[max];
  InitializeMemory(maxItems, storage);
  listData = NUL;
}

ListType::ListType()
{
  length = 0;
  maxItems = 500;
  storage.nodes = new NodeType[500];
  InitializeMemory(500, storage);
  listData = NUL;
}

ListType::~ListType()
{
  delete [] storage.nodes;
}

void InsertItem(ItemType item)
{
  // STUB: REPLACE WITH USEFUL CODE.
}