CSC152 2006S, Class 1: About the Class

Admin:
* URL: http://www.cs.grinnell.edu/~rebelsky/Courses/CS152/2006S/
* No office hours today
* Homework!
* Meet Eryn, "Ms. O'Neil, Sir/Ma'am"

Overview:
* Subject matter(s) of the course
* Administrative issues

CSC152, Fundamentals of Computer Science II
* Course in Computer Science (what is "Computer Science"?)
  * Science of information processing (taking something you already know and finding out something you don't know)
  * Problem solving for programming
* Terms
  * Science: Scientific Method
    * A method of study in which you start with observation
      form a hypothesis,
      design an experiment that lets you test the hypothesis,
      conduct the experiment,
      interpret the results ("prove" or "disprove")
      back to the beginning ('refine hypothesis')
    * Unfortunately, computer scientists rarely use the scientific method
  * Programming: Explaining problems to a computer
  * Hypothesis: Educated guess (went to a good school)

* Study computation (algorithms and data)

CS152: Algorithms and Abstract Data Types
* Algorithm: Formal instructions for solving a problem
* Abstract Data Type (ADT): description of the abilities of data
  Lists in Scheme: Lists are collections of data which provide
    N key operations:
    nil: make empty list
    cons: add something to the front of a list
    car: grabs front of list
    cdr: grabs all but front of list
    null?: determine if a list is empty
* Data Structures: How to implement ADTs
  * Lists in Scheme are implemented with "pairs" of pointers

Also: Object-Oriented Programming
* Perspective for representing algorithms and data
* Represent programs in terms of communicating objects
  * "Object": Data plus capabilities (functions)
* Also ...
  * Encapsulation - Data in an object are protected; access only through methods
  * Inheritance - Can define new objects in terms of old
  * Polymorphism - Can use a variety of objects for the same task

Also: Java - provides a context
* Very popular programming language
* Object-oriented
* Does not look like Scheme
* Trusts you less than Scheme

Homework (to help you think about ADTS and OOPS): 
* What are the key operations for rational numbers?
* Classify them