OOP Primer

1
OOP Primer

• Bus 92Fall 2007
• Notes on Wang, 2006

2
Learning to Program involves

• How to solve a particular problem
• How to use a particular programming language
• How to use a specific program to help you write
  programs in your chosen programming language
• Editor to write, edit and save your program
• Compiler to translate the program from a
  high-level programming language (Basic) to a
  lower level computing language (machine code)
• VB Express is an integrated development
  environment (IDE) that includes both an editor
  and compiler

3
The Hierarchy of Programming Languages
Visual Basic
C
LISP
Compile
Assembly
Machine Code 1110 0110 1111
4
Programming Language Components
Statements
To form
Programs
Combine according to
Syntax
Building Blocks
Functions
Keywords
Functions
Keywords
Keywords
5
Example
MsgBox
Dim Counter as IntegerCounter 1 Do While
Counter lt10 MsgBox (Counter) Counter
Counter 1 Loop
Syntax
Dim
Do
Integer
While
Loop
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Every VB Program is composed of

• A User interface
• Get data -- keyboard, mouse
• Display information -- printer, screen
• Instructions that make your program do something
  useful
• Manipulate and respond to data -- add two
  numbers, select data from a table

7
oop

• A programming model that facilitates division of
  a program into smaller parts according to 3 core
  ideas
• Encapsulation
• Inheritance
• Polymorphism

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Encapsulation

• Objects store both data and the methods that
  manipulate the data in a single location
• Protects data from being changed by other parts
  of the program

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Inheritance

• Code reuse by copying makes it hard to trace
  location of copied code and apply edits
• With inheritance, object b uses the code stored
  in object a without copying the code
• Code fixes/updates in object a automatically
  fix/update code in object b

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Polymorphism

• Objects can inherit method names from other
  objects
• Inherited methods can operate according to new
  code that results in different behaviors vs
  method from source object

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Class/Object/oop example
Class Game Characters
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Match the core idea to the example
The Dragon object inherits the die method from
the prince object
The Dragon objects move method specifies slow
progressthrough the screen while the Prince
objects move methodspecifies quick leaps across
the screen
Changes to the Dragons move method do notaffect
the Prince objects move method
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Software Development Lifecycle (SDLC)
Project Planning, Feasibility Analysis
Systems Analysis
Systems Design
Implementation
Integration Testing
Acceptance Implementation Deployment
Maintenance
Bus 92 (overview)
Bus 110B
Bus 119A (mastery)
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Casual Use Cases

• Describe how the application will be used by a
  user to achieve a specific goal
• Identify the goal of the system
• List the key steps to achieve the goal
• Amazon.com example

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In Class Activity

• Describe your application to your partner(s)
• Ask questions if the description is unclear
• Be ready to describe your partners application
  to the class
• Build an initial use case for your application to
  share in class

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HW2

• Write a use case of the main user interaction
  with the application that you plan to build for
  the class. Send the use case via email (not an
  attachment) to 92thurs07_at_sbcglobal.net by noon on
  Thursday, Sept 6, 2007
• Read Wang Chapters 1-6. Try to do the exercises
  at home if you can install VB Express on your
  machine
• Bring your flash drive to class labeled with your
  first name, last name, student ID