CSC151 2007S, Class 02: An Introduction to CSC151

Admin:
* Due: Intro surveys
  * Many of you need to learn to follow directions (or at least
    check to see if a handout is double-sided)
* Advance note about email subjects
  * USE THEM!
  * When you're asking for help, include something about that in the
    title
    HW3
    vs
    "I need ****HELP**** on hw3! PLEASE!"
* Reading for Friday:
  * The GNU Image Manipulation Program
* Responses to intro surveys will probably come over the weekend.
* No office hours again today!  (Sorry; try email)
* Don't be late or Sam will make fun of you
* Extra credit for attending tomorrow's Thursday extra
  * COmputer-assisted bargello quilt design
  * 4:30 in 3821
  * Snacks at 4:15 in the CS Commons

Overview:
* Lessons from day one.
* Common parts of an algorithm.
* About the course.
* Getting started with Linux.
* Some administrative details. (If there's time.)

==Lessons from Smiley Faces==

* Goal: Instructions for drawing smiley faces
* Limitation: Different "basic instructions"

* What, if anything, did you learn from that exercise?
* Be specific, or the computer may misinterpret
* You need to know the basic capabilities from which you build the
  algorithm
  * Don't assume too many prior skills
* It's helpful to work together - Other people might have other
  knowledge
* Computers are literal
* Things that seem simple might actually be complex when you try to
  explain them
* Sometiems things are designed badly, and can be hard to use
  * It's not your fault! (unless you are the designer)
* UM is a good default answer
* Don't just write instructions, read over them and think about them

==So, what does an algorithm look like, anyway?==

* What do they look like?
  * Varies greatly
* What goes in them?
  * A few common things
* A lot like recipies in a cookbook
  * Instructions can be very detailed step-by-step instructions
  * Experienced cooks may only need an ingredient list

* Name things
  * The bowl of dry ingredients
  * The bowl of wet ingredients
  * The pen in your hands
* Use some basic actions
  * Pour, mix, shove in oven
  * draw a circle of radius N in color C
* Repeat actions
  * Stir fifty times
  * Knead until the dough has the consistency of an earlobe
  * Do the following steps 360 times
    forward one inch
    turn clockwise one degree
* Conditionals
  * If you are in Denver or other too-high city, set your oven to 300 degrees
  * Othewise set it to 350 degrees
  * If the cap is not yet off, remove the cap.
* subroutines/procedures
  * An algorithm that can be used by another algorithm
  * Combine pixel "draw circle" with "draw a smiley face with pixels"

== Time for Lab ==

* If you got a password or know your password, follow the instructions
* If you did not get a password 
  * follow along with a colleague
  * after class, visit Mr. Stone (3826 or so) and get a password
  * then do the lab on your own (or at the start of next class)