// FILE: sequence2.h
// CLASS PROVIDED: sequence (part of the namespace main_savitch_4)
// There is no implementation file provided for this class since it is
// an exercise from Chapter 4 of "Data Structures and Other Objects Using C++"
//
// TYPEDEFS and MEMBER CONSTANTS for the sequence class:
//   typedef ____ value_type
//     sequence::value_type is the data type of the items in the sequence. It
//     may be any of the C++ built-in types (int, char, etc.), or a class with a
//     default constructor, an assignment operator, and a copy constructor.
//
//   typedef ____ size_type
//     sequence::size_type is the data type of any variable that keeps track of
//     how many items are in a sequence.
//
//   static const size_type DEFAULT_CAPACITY = _____
//     sequence::DEFAULT_CAPACITY is the initial capacity of a sequence that is
//     created by the default constructor.
//
// CONSTRUCTOR for the sequence class:
//   sequence(size_t initial_capacity = DEFAULT_CAPACITY)
//     Postcondition: The sequence has been initialized as an empty sequence.
//     The insert/attach functions will work efficiently (without allocating
//     new memory) until this capacity is reached.
//
// MODIFICATION MEMBER FUNCTIONS for the sequence class:
//   void resize(size_type new_capacity)
//     Postcondition: The sequence's current capacity is changed to the 
//     new_capacity (but not less that the number of items already on the
//     list). The insert/attach functions will work efficiently (without
//     allocating new memory) until this new capacity is reached.
//
//   void start( )
//     Postcondition: The first item on the sequence becomes the current item
//     (but if the sequence is empty, then there is no current item).
//
//   void advance( )
//     Precondition: is_item returns true.
//     Postcondition: If the current item was already the last item in the
//     sequence, then there is no longer any current item. Otherwise, the new
//     current item is the item immediately after the original current item.
//
//   void insert(const value_type& entry)
//     Postcondition: A new copy of entry has been inserted in the sequence
//     before the current item. If there was no current item, then the new entry 
//     has been inserted at the front of the sequence. In either case, the newly
//     inserted item is now the current item of the sequence.
//
//   void attach(const value_type& entry)
//     Postcondition: A new copy of entry has been inserted in the sequence after
//     the current item. If there was no current item, then the new entry has 
//     been attached to the end of the sequence. In either case, the newly
//     inserted item is now the current item of the sequence.
//
//   void remove_current( )
//     Precondition: is_item returns true.
//     Postcondition: The current item has been removed from the sequence, and the
//     item after this (if there is one) is now the new current item.
//
// CONSTANT MEMBER FUNCTIONS for the sequence class:
//   size_type size( ) const
//     Postcondition: The return value is the number of items in the sequence.
//
//   bool is_item( ) const
//     Postcondition: A true return value indicates that there is a valid
//     "current" item that may be retrieved by activating the current
//     member function (listed below). A false return value indicates that
//     there is no valid current item.
//
//   value_type current( ) const
//     Precondition: is_item( ) returns true.
//     Postcondition: The item returned is the current item in the sequence.
//
// VALUE SEMANTICS for the sequence class:
//    Assignments and the copy constructor may be used with sequence objects.
//
// DYNAMIC MEMORY USAGE by the List
//   If there is insufficient dynamic memory, then the following functions
//   throw a BAD_ALLOC exception: The constructors, insert, attach. 

#ifndef MAIN_SAVITCH_SEQUENCE_H
#define MAIN_SAVITCH_SEQUENCE_H
#include <cstdlib>  // Provides size_t

namespace main_savitch_4
{
    class sequence
    {
    public:
        // TYPEDEFS and MEMBER CONSTANTS
        typedef double value_type;
        typedef std::size_t size_type;
        static const size_type DEFAULT_CAPACITY = 30;
        // CONSTRUCTORS and DESTRUCTOR
        sequence(size_type initial_capacity = DEFAULT_CAPACITY);
        sequence(const sequence& source);
	~sequence( );
        // MODIFICATION MEMBER FUNCTIONS
	void resize(size_type new_capacity);
        void start( );
        void advance( );
        void insert(const value_type& entry);
        void attach(const value_type& entry);
        void remove_current( );
        void operator =(const sequence& source);
        // CONSTANT MEMBER FUNCTIONS
        size_type size( ) const;
        bool is_item( ) const;
        value_type current( ) const;
    private:
        value_type* data;
        size_type used;
        size_type current_index;
	size_type capacity;
    };
}

#endif