1. An Introduction to Programming and VB.NET
Chapter 1
An Introduction to Programming and VB.NET

2. Learning Objectives
Understand importance of information systems in organizations
List and discuss the six computer operations
Discuss the role of computer programs and programming languages
Understand concepts of object-oriented programming in Windows and in VB .NET
List and discuss the steps in developping an application in VB .NET

3. Information System
The combination of technology (computers) and people that enables an organization to collect data, store them, and transform them in useful information

4. Software List of instructions: Programs
Creation of those instructions: Programming
Programming is part of :System Development

5. Development Identify the problem Analyze the system Design the system
Implementation (construction)

6. Computer Operations Input data Store data in internal memory
Perform arithmetic on data
Compare two values and select an action accordingly
Repeat a group of actions a number of times
Output the results of precessing

7. The Six Computer Operations

8. Input Data From a keyboard From a mouse From barcode reader
From data files
From sensors

9. Store Data in Memory Memory location are called Variables
Having data in memory allows rapid access
Data in memory is not static, it is allowed to be changed by the program

10. Perform Arithmetic on Data
Includes
Addition
Subtraction
Division
Multiplication
Most manipulation on data in memory can be seen as arithmetic manipulation

11. Compare and Select Action
Compare two numerical values
If A>B then do something …
Compare textual values
If Name1 = Name2 then …

12. Repeat Actions a Number of Times
Keep checking if the next name in a list is the same as that of the user
Keep adding item prices in a grocery list to return the total
The computer is king of repetitions!

13. Output Results To be useful, the result must be made accessible
On a monitor
Printed on paper
Saved in a file on disk

14. Programs and Programming
Solution must be a list of steps, this is the algorithm
The algorithm is not bound to a programming language, see it as the “English” version of the program
The algorithm is more important than the language

15. Control Structures Sequence : ordered list of operations
Decision : control the flow of operation
Repetition : repeat operations until a certain exit condition is met

16. Programming in Windows
Windows is based on events
A key being pressed is an event
The mouse moving is an event
Clicking the mouse is an event
Double clicking is an event

17. VB .NET Language It allows event-driven programming
It is object-oriented
Everything revolves around objects
Each object has properties and methods
Properties are characteristics
Methods are actions the object can take
Some objects can raise events, i.e. notify other objects that something happened

18. Characteristics of OOP
Encapsulation
black box view of an object
what is accessible is key, not how it is made accessible
Inheritance
allows for specialization of classes
Polymorphism
Different classes (objects) being allowed to be accessed the same way
Dog.Run()
Cat.Run()

19. Programming in VB .NET Define problem Create interface
Develop logic for action objects
Write and test code for action objects
Test overall project
Document project in writing

20. Case Study: Vintage DVDs
Want to calculate the taxes and total amount due on a DVD rental

21. Step 1: Definition of Problem
Identify input
Price of DVD
Identify output
Taxes
Amount due
Identify actions to take
Calculate
Quit the program

22. Step 2: Creation of Interface
Make a sketch by hand
Decide on the objects required
TextBoxes, Buttons, Labels, etc
Drag and drop the objects on the form
The layout should be logical
Group related objects together
The layout should be eye pleasing
Avoid to many fonts and loud colors

23. Step 3: Logic for Action Objects
IPO (Input/Processing/Output) Table
For each object, it shows the input, the output, and what processing needs to be done to get from one to the other
Pseudo code
Step by step instructions in the English language rather than in a given programming language.
Pseudo code is more natural to the human and is easy to translate to programming language

24. Step 4: Write and Test Code
Translate pseudocode or IPO tables into the syntax of the programming language
Test the code by “running” it in the MSDE
Test often, every few lines of code written
Make use of test data
Test ideal conditions
Test problematic conditions

25. Step 5: Test Overall Project
Test communication between objects
Make sure the program meets requirements

26. Step 6: Document Project
Documentation
The written description of the software that aid users and other programmers
Internal documentation
Comments in program to explain the purpose and logic of the code
Comments are as important as the code
Comments allow for maintenance of the code
Comments start with an apostrophe ( ‘ )

27. Final Remarks
The development process should be seen as iterative, you will not get the final solution on the first try
You should
Design a little
Code a little
Test a little
Document a little
And then repeat the process again and again

28. Copyright 2004 John Wiley & Sons, Inc.
All rights reserved. Reproduction or translation of this work beyond that permitted in section 117 of the 1976 United States Copyright Act without express permission of the copyright owner is unlawful. Request for further information should be addressed to the Permissions Department, John Wiley & Sons, Inc. The purchaser may make back-up copies for his/her own use only and not for distribution or resale. The Publisher assumes no responsibility for errors, omissions, or damages caused by the use of these programs or from the use of the information herein