Visual C++ Programming: Concepts and Projects Chapter 12B: Linked List (Tutorial)

Visual C++ Programming: Concepts and Projects

Chapter 12B: Linked List (Tutorial)

Tutorial: Linked List

• Problem description– This program helps the user visualize a linked list

by drawing one on the interface– Buttons are provided to:

• Create the initial list• Add a Node to the front of the list• Delete a Node from the front of the list• Remove all Nodes (delete the list)

2Programming with Visual C++

Problem Description


Problem Description (continued)


Design

• The Node class definition– Start with a UML class diagram– All data members and methods will have public

access (+)– Class variable: nodeCount– Instance variables: nodeData, next– Default constructor: Node()


Design (continued)


Design (continued)

• Interface sketch– Equal distance between Node rectangles– Arrows drawn to link Nodes– Starting coordinates of the first Node are crucial

• The positions of all other Nodes are calculated from them


Design (continued)


Design (continued)

• The head pointer

• The head pointer always points to the first Node in the list

• All insertions and deletions involve the head pointer


Design (continued)

• Table of constants


Design (continued)

• Table of Drawing objects


Design (continued)

• Creating the first Node in a linked list


Design (continued)

• Inserting a new Node– Create the new Node– Point the new Nodes next pointer at the first

Node in the list– Assign the head pointer to point to the new Node

• This always inserts the new Node at the head of the linked list


Design (continued)


Design (continued)

• Deleting a Node– Create a temporary Node pointer (temp)– Point temp at the first Node in the linked list– Assign the head pointer to point to the second

Node– Delete the Node pointed to by temp

• This always deletes the Node at the head of the linked list


Design (continued)


Design (continued)

• Use a loop to delete each node in the list• Delete from the front• Reassign head to point to the next Node• Delete Nodes until there are no more


Design (continued)


Development

• Interface– Only four buttons required

• Coding– Create Node.h (Node header file)– Create Node.cpp (implementation file)– Finish coding Form1.h (client code)


Development (continued)



• The Node class contains a default constructor– Change this to a prototype– Put the default constructor code in the

implementation file (Node.cpp)



• Enter the code for the Node class in Node.h



• Write the default constructor code in the implementation file (Node.cpp)

• Remember to include Node.h



• Client code (Form1.h)– Include the Node class definition file (Node.h)



• Client code (Form1.h)– Constants, head pointer, and Drawing objects



• Client code (Form1.h)– Code Form1->Load()

• Instantiate Drawing objects



• Client code (Form1.h)– Code the reset() method

• Properly enable all buttons• Reset class variable Node::nodeCount to 0


Coding

• Write code for btnHead_Click()– Create new head pointer– Draw the linked list– Properly reset the buttons


Coding (continued)

• Write the code for btnInsert_Click()– No more than seven Nodes allowed– Implement three-step insertion algorithm– Draw the linked list


Coding (continued)


Coding (continued)

• Code drawNode()– drawNode() is recursive– level is used to determine when to stop

drawing Nodes– The location of each Node rectangle is calculated

by multiplying nodeDistance and level


Coding (continued)


Coding (continued)

• Draw the current Node• If there is another Node linked to it (next is

not the nullptr), then draw that Node– This is a recursive process– The base case occurs when next is the nullptr


Coding (continued)


Testing

• Check each button– Create a list– Insert nodes (make sure the nodeData is correct)– Try to insert more than seven (not allowed)


On Your Own

• Task 1. Coding btnDelete_Click()• Task 2. Coding btnClear_Click() and deleteList()

• Task 3. Final Testing to make sure all buttons work correctly

Programming with Visual C++ 54

On Your Own (continued)


Visual C++ Programming: Concepts and Projects Chapter 12B: Linked List (Tutorial)

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