// *********************************************************
// Header file ListA.h for the ADT list.
// Array-based implementation.
// *********************************************************
const int MAX_LIST = maximum-size-of-list;
typedef desired-type-of-list-item listItemType;

class listClass
{
public:
   listClass();  // default constructor
                     // destructor is supplied by compiler

// list operations:
   bool ListIsEmpty() const;
   // Determines whether a list is empty.
   // Precondition: None.
   // Postcondition: Returns true if the list is empty,
   // otherwise returns false.

   int ListLength() const;
   // Determines the length of a list.
   // Precondition: None.
   // Postcondition: Returns the number of items
   // that are currently in the list.

   void ListInsert(int NewPosition, listItemType NewItem,
                   bool& Success);
   // Inserts an item into a list.
   // Precondition: NewPosition indicates where the 
   // insertion should occur. NewItem is the item to be 
   // inserted.
   // Postcondition: If insertion was successful, NewItem is 
   // at position NewPosition in the list, other items are 
   // renumbered accordingly, and Success is true; 
   // otherwise Success is false.
   // Note: Insertion will not be successful if
   // NewPosition < 1 or > ListLength()+1.

   void ListDelete(int Position, bool& Success);
   // Deletes an item from a list.
   // Precondition: Position indicates where the deletion 
   // should occur.
   // Postcondition: If 1 <= Position <= ListLength(),
   // the item at position Position in the list is
   // deleted, other items are renumbered accordingly,
   // and Success is true; otherwise Success is false.

   void ListRetrieve(int Position, listItemType& DataItem, 
                     bool& Success) const;
   // Retrieves a list item by position number.
   // Precondition: Position is the number of the item to 
   // be retrieved.
   // Postcondition: If 1 <= Position <= ListLength(),
   // DataItem is the value of the desired item and
   // Success is true; otherwise Success is false.

private:
   listItemType Items[MAX_LIST];  // array of list items
   int          Size;             // number of items in list

   int Index(int Position) const;
   // Converts the position of an item in a list to the 
   // correct index within its array representation.
};  // end class
// End of header file.