CSC302 2007S, Class 19: Basics of Object-Oriented Programming

Admin:
* Due: HW5.
* Wednesday and Friday, you will be watching videos in class.  
  In lieu of reading response, please send me one-paragraph 
  responses to those videos after you watch the videos.
  * Please help the Adm. Asst. set up the video.
* The reading for Monday the 12th is a long online document. 
  See the link in today's page (and elsewhere)
* About citation.
* The Mid-Semester Exam is ready.

Overview:
* What is object-oriented programming?
* Three key issues: Encapsulation, Inheritance, Polymorphism.
* Why OOP?
* A biased history.
* Polymorphism vs. Overloading.

/About Citation/

* This is an incorrect URL
  http://urlcollector.org?istolethisfrom=http://www.wikipedia.org/eng/polymorphism
* This is not a citation.
  "Taken from Wikipedia"
* This is not a citation, but it's better.
  http://en.wikipedia.org/wiki/Polymorphism_%28computer_science%29
* This is not a citation, but it's better
  http://en.wikipedia.org/wiki/Polymorphism_%28computer_science%29
  (Dated ___; Visited ___)
  * Ideally, you keep a copy, too.
* This is a citation
  AUTHOR (YEAR).  TITLE.  Online resource at
  URL (Dated ___; Visited: ___).

Related issue: Give author names, quotes, and pages, when referring to papers
  "The author of the first paper claims that object-oriented programming is useless."
  "On p. 5 of "Why Scheme Rules", J. Fred Schemer notes that "Every design pattern is automatic in Scheme, so why would anyone use OOP?""

/Finally!  What is OOP/

* 3.5 main paradigms of language design:
  * Imperative - 
    * Emphasizes side effects: Moving values to and from memory
    * Sequenced
  * Declarative
    * Say what you want, not how to compute it
      * grep:  grep "^[^a-z]" foo.txt
      * SQL: select F.foo,B.bar from F,B where F.baz=B.bam
      * Prolog: 
    * Pure functional programming (+ 0.5)
        (define (foo x) (bar (baz x) (bam x)))
  * Object-oriented
    * 'Everything' is an object vs. "the building blocks of the program"
    * An object has data and methods to manipulate the data

Why OOP?
* Good for software engineering
  * Encapsulation helps segment concerns - Modfiication of one
    object should not affect others, as long as the "interface"
    is maintained
  * Inheritance and Polymorphism make programmers more efficient
* Pointy-haired bosses like buzzwords?