Overview

• Preliminaries.
  • Admin.
  • Homework.
  • Questions.
• Lessons from day one.
• Common parts of an algorithm.
• About the course.
• Getting started with Linux. [1:40-2:05]

Preliminaries

Admin

• Sam forgot the attendance sheet. We'll do attendance again on Wednesday.
  • Handing out accounts is a form of attendance. Not here: BT
• Mr. Stone will be visiting class to bring your account information.
  • Separate from the rest of campus
  • So you get a new password
  • Mr. Stone wrote one for you
  • You should change it
  • If you had one already, you don't get one
  • If you don't remember, go to Mr. Stone's office
  • And you can watch him show me up on correct pronunciation of names
  • Mr. Stone is happy to talk to you about the software we have available, the wonders of open source, and the evils of the NSA
• When doing recitation, I will call on you in physical order in today's class.
• Welcome to our guest mentors, Toby B and Alex G
• Extra credit:
  • Thursday extra on summer research in CS, Thursday @ 4:30 in Noyce 3821.
  • CS Table Friday at noon in the Day PDR in the Marketplace: 3D Printing and Cyborg Pars

Homework

• Don't forget that the first assignment is due at 10:30 p.m. tonight. I appreciate that assignments have started arriving.
• There are lots of readings for tomorrow's class, but they are all short.

Questions

Are there questions on or from the homework?

Can you correct your homework, as long as you submit it before the due date?

Certainly. But the odds are about 20% that I'll grade the wrong assignment.

Are there questions from the readings (other than the ones that I plan to ask you)?

Lessons from day one

Review: Some things we commented about yesterday, and some followup comments from SamR.

Summary of yesterday

• Cs is the study of algorithms, algorithms are instructions.
• Yesterday's exercise: Instructions to make nut butter and jelly.

Things we learned

• When writing instructions, know what your audience knows.
  • Part of learning to write algorithms is learning the basic set of instructions you can use.
• Be specific. If your audience can misinterpret you, it will.
  • Computers are sentient and malicious.
• When things go wrong, it's funny, not painful (well, except for me).
  • Be positive!
• You write better algorithms if you can observe them working step by step.
  • We'll work in a development environment in which you can play with small instructions.
• You write better algorithms when you write them with other people.
  • And so we force you to do so
• Know your data - (Screw-top vs pop top).
  • We'll learn a new kind of information (e.g., number, string, picture) and the operations that we can use on that information
• Watch for infinite loops.
• Computers seem to intentionally misinterpret instructions.
• Keep instructions simple, if possible.
• Testing should be rigorous and thorough.

Common components of an algorithm

You did a reading about this.

What are some parts of an algorithm?

• Subroutines - A named section of code, that you can use again and again
  • How to open a jar if it's a screw-top jar unscrew the top by grasping the bottom with your dominant hand, the top with your non-dominant hand, placing the top toward the ceiling, and rotating your non-dominant hand counter-clockwise otherwise, if it's a pop-top jar ... otherwise throw it against the wall and cross your fingers
• Variables - , names of things
• Similar: Parameters Inputs to subroutines
• Conditionals - If ... Might or might not do something. (Make a choice.)
  • If you grabbed the knife incorrectly, switch ends
  • If the stay-fresh seal is on top, ...
• Repetition - It's repeating the same action again and again and again
  • "Turn non-dominant hand counter-clockwise until the lid comes off"
  • Be careful about doing repeating forever

About the course

• You probably learned a bit in the first assignment.
• You'll learn more over the first week.

Getting started with Linux

• Yay! Learn how to use the bunsen burners and test tubes.
  • No, not really, but the same depth of learning.
  • These are the things that help you get the real work done.
• It's sad when a CS prof can't write good instructions, isn't it?