/************************************************************/
/* ADAPTED FROM:                                            */
/* http://www.cs.colorado.edu/~main/chapter4/node1.cxx      */
/*                                                          */
/* Main and Savitch, "Data Structures and Other Objects     */
/*    using C++", 2nd edition, Addison-Wesley, Ch.5         */
/************************************************************/

//---------------------------------------------------------------------
// File: node.cpp
// Name: Michael Main, Walter Savitch
//       (adapted by Sharon M. Tuttle)
// last modified: 3-10-05
//
// Class name: node
//
// Purpose: serves as the unit from which a singly-linked list
//    can be built.
// 
// DYNAMIC MEMORY USAGE by the node class:
//    If there is insufficient dynamic memory, then the
//       following throw bad_alloc:
//          the constructors, 
//
// NOTE: 
//    Some of the methods have return value that is
//       a pointer to a node. Each of these comes in TWO
//       versions: a non-const version (where the return value is
//       node*) and a const version (where the return value is
//       const node*).
//---------------------------------------------------------------------

#include <cassert>
#include "node.h"
using namespace std;

/*****************************************************/
/* CONSTRUCTORS and DESTRUCTOR                       */
/*****************************************************/

//---------------------------------------------------------------------
// postcondition: creates a node with data_field obtained from
//    the default constructor of the value_type, and
//    next_field set to NULL.
//
// NOTE: In the ANSI/ISO standard, this default-constructor
//     notation is also allowed for the built-in types, 
//     providing a default value of zero.
//
node::node( )
{
    data_field = value_type();
    next_field = NULL;
}  

//---------------------------------------------------------------------
// postcondition: creates a node with data_field set to
//    init_data, and next_field set to NULL.
//
node::node(const value_type& init_data)
{
    data_field = init_data;
    next_field = NULL;
}

//---------------------------------------------------------------------
// postcondition: create a node with data_field obtained from
//    the default constructor of the value_type, and
//    next_field set to init_next.
//
node::node(node* init_next)
{
    data_field = value_type();
    next_field = init_next;
}

//---------------------------------------------------------------------
// postcondition: create a node with data_field set to
//    init_data, and next_field set to init_next.
//
node::node(const value_type& init_data, node* init_next)
{
    data_field = init_data;
    next_field = init_next;
}

/*************************************************************/
/* ACCESSORS and other constant member functions (observers) */
/*************************************************************/

//---------------------------------------------------------------------
// postcondition: returns the data from this node
//
node::value_type node::get_data( ) const
{
    return data_field;
}
   
//---------------------------------------------------------------------
// postcondition: returns the next pointer from this node.
//    (See note above --- need both a const and non-const
//    version of this, because it returns a pointer.
//    See also pp. 219-221 of Savitch and Main, 3rd edition.)
//
const node* node::get_next( ) const
{
    return next_field;
}

node* node::get_next( )
{
    return next_field;
}
        
/*****************************************************/
/* MODIFIERS and other modifying member functions    */
/*****************************************************/

//---------------------------------------------------------------------
// postcondition: the node now contains the specified
//    new_data.
//
void node::set_data(const value_type& new_data)
{
    data_field = new_data;
}

//---------------------------------------------------------------------
// postcondition: the node now contains the specified
//    new_next pointer.
//
void node::set_next(node* new_next)
{
    next_field = new_next;
}