Due: 9/27/01

This programming assignment is designed to introduce the use of Link Lists to:

• implement a List data structure container
• continue the use of a ListBox
• introduce the use of 'Nodes' that make up the elements in the List

NOTE ON THE USE OF PREVIOUS FILES - Don't

You will probably want to use much of the code that you developed for assignment #4. To do that, follow these suggestions

1. Create your new project 6
2. Copy/paste the .h and .cpp files from assignment 4 into your new project 6 directory
3. From the 'file' view, right click on the ProjectFiles entry and select 'Add file to project'
4. Modify the copied files to meet the new specifications

In order to meet these goals you will keep the user interface from Assignment #4

• an edit box for entering a CString
• an edit box for displaying messages (type CString)
• a button labeled Insert
• a button labeled Find
• a button labeled Remove
• a button labeled Empty?
• a button labeled Full?
• a ListBox

Since 'Nodes' make up the elements of the list you will need to define either a Class or Struct of type Node. It should contain the following members:

• Node(); // Default constructor
• Node(CString arg); // An overloaded constructor
• CString m_data; // The data in the list is held in individual Nodes
• Node * m_next; // A pointer to the next Node in the list
• Node * m_previous; // A pointer to the previous Node in the list

Your Class CList should contain the same public member functions as Assignment #4. The m_data member should be renamed to m_Head of type Node *; i.e. m_Head will be the address of the 1st Node in the list. Be sure to remember to have the CList() constructor initialize m_Head to NULL.

The behavior of your program should be as follows:

• When Button Insert is clicked the CString in the edit box is added to the 'list' by dynamically allocating a new Node, put the CString into the Node's m_data field and the contents of the List should be displayed in the ListBox.
• When Button Find is clicked you should search the 'list' for the CString that was specified in the edit box and display SUCCESS or FAILURE in the Message-edit-box
• When Button Remove is clicked you should
  • Find a Node that contains a matching CString
  • Delete the Node from the list
  • If the Node had a 'next' and a 'previous' Node be sure to make them point to each other
  • If the List was modified, the contents of the List should be redisplayed in the ListBox and REMOVED should be displayed in the Message-edit-box.  If it was not present, NOT FOUND should be displayed in the Message-edit-box.
• When Button Empty? is clicked a message should appear indicating TRUE or FALSE
• When Button Full? is clicked a message should appear indicating TRUE or FALSE

Testing:

1. Click Empty
2. Click Full
3. Click Remove
4. Insert a CString
5. Click Empty
6. Click Full
7. Click Find
8. Click Remove
9. Click Find
10. Click Empty
11. Click Full

Follow the above steps BEFORE you even try inserting 2 or more items into the list. When the list goes from 'empty' to have 1 Node in the list is one of the hardest places to get correct.