Course Introduction

1
Course Introduction

• CIS 234
• Object Oriented Programming

2
DO NOT TAKE THIS COURSE

• Unless You Have 15 Hours a Week for It

3
You Will Have Difficulty With This Course

• If You Do Not Have Your Own Computer

4
My Expectations of You

• Attend every class
• Work hard
• Do all the assignments
• Apply your best organizational skills
• Do your own work
• Ask help if needed
• Help others

5
Things To Do

• Read the syllabus -- jot down any questions
• Buy the textbook at Ask Copy Center
• Check Out the class Web site
• Student Survey
• Download the survey document from the Class Web
  site
• Complete the survey
• e-mail completed survey to Dr. Bell
• Smalltalk Mutual Support Discussion List
• Access the List
• Read Dr. Bell's Posting that includes the
  assignment
• Post to the discussion list as per the assignment

6
Things to Do (continued)

• Read Chapters 1-3 and review the chapter
  questions
• Download and Review PowerPoint slide sets
  CourseIntro.ppt and CIS23401.ppt -- print these
  out 6 per page
• Borrow Smalltalk CD-ROM from the Library Reserve
  Desk
• Install Smalltalk on your system as per
  instructions (instructions included with CD and
  also on Web site)

7
Things to Do (continued)

• Get started on Assignment 4-4 as described on the
  Web site

8
Definitions

• Programming
• Objects
• Real Objects
• Software Objects
• Object-Oriented Programming
• Smalltalk
• Visual Age

9
What We Will Be Doing

• Learning the Smalltalk (ST) language
• Learning to analyze business processes and
  determine key information
• Learning to develop computer programs (systems)
  that meet customer specifications to improve
  business processes
• Learning to professionally document the systems
  we develop

10
The Smalltalk Environment

• Bringing up ST
• Creating a new Workspace
• Entering ST expressions
• Executing ST expressions
• Display
• Execute
• Inspect
• Saving your program

11
Structure of a ST Expression

• The Model
• receiving object name selector argument(s)
• Samples
• testAmt 2.0.
• 40 8.
• oldTaxesPayable newTaxesPayable 1.5.
• Date today.

object that receives the message
the instruction or message
optional values necessary for the instruction to
be followed
12
ST Expressions (continued)

• The Model
• receiving object name selector argument(s)
• Samples
• 5 factorial.
• checkOutDate subtractDate checkInDate.
• 'Adam Nguyen' at 6.
• Array new 4.
• Array with 'Joan' with 'Ann' with 'Barbara'.
• inputFile close.
• myCustomer inspect.

13
What Happens When a ST Expression is Evaluated

• Any errors are identified and must be corrected
  before execution can proceed
• errors could be undeclared variables
• errors could be variables that do not have values
• errors could be objects that do not understand
  messages
• errors could be incorrect messages for the
  objects
• errors could be incorrect arguments for the
  messages
• Successful execution of a ST expression will
  create a new object
• The new object can be used in an assignment
  statement or in a different expression

14
At Home Test the Following

• 40 2.
• 40.0 2.0.
• 5 factorial
• 'Sam Witherspoon' at 5.
• 'Andrea Deoc' at1.
• Date today.
• (Date today) addDays 20.

15
For Each of the Following

• Identify the Receiving Object, the Selector and
  the Argument
• 40 2.
• 40.0 2.0.
• 5 factorial.
• 'Sam Witherspoon' at 5.
• 'Andrea Deoc' at1.
• Date today.
• (Date today) addDays 20.

16
Assignment Statements

• use the assignment operator
• have a variable name to the left of the
  assignment operator
• have a valid ST expression to the right of the
  assignment operator
• the variable name will "point at" the object
  created by the ST expression on the right side of
  the assignment operator
• Sample
• newTaxes oldTaxes 1.1.