CS1321 Introduction to Computer Science

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CS1321Introduction to Computer Science
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Welcome

• Were glad youre here.
• We hope you will
• learn useful things.
• Find the course challenging.
• Have fun!

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Lecturers (in no particular alphabetic order)

• David Dagon dagon_at_cc.gatech.edu
• Room 121 in the College of Computing
• Dan Lerner lerner_at_cc.gatech.edu
• Room xxx in the College of Computing
• David Smith dmsmith_at_cc.gatech.edu
• Room 123 in the College of Computing
• Monica Sweat sweat_at_cc.gatech.edu
• Room 120 in the College of Computing

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Why take CS1321

• Required, but why?
• Pervasiveness of Computing Technology
• Probably eventually work with computers
• Will definitely work with computer people
• Critical resources for Tech Experience
• More later...

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Misconceptions

• All computer programming is done by computer
  scientists.
• Im a(n) (engineering/architecture/music/managemen
  t) major. Why would I ever use this stuff?
• I don't need to know how to program.

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Course Objective

• It is
• To learn how to design programs
• It is not
• To learn goofy program syntax
• To learn how to count parentheses
• To make your life unbearable
• although at times you will probably think it
  is all of these at once

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University Vocabulary

• Lecture Typically led by Professor or Lecturer.
  Sometimes big.
• Lab Formerly held in equipped laboratory,
  involving immediate hands on doing. Now hands on
  projects done on your own.
• Recitation Typically led by Teaching Assistant
  (TA). Smaller group. Questions and answers.

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Lecture

• You are here!
• Will generally follow the material in the text
  book, but will usually work through different
  examples.
• Questions welcome.
• All sections should be synchronized
• Attendance strongly encouraged
• Clear link between attendance and grades

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Lab

• Required by your department
• Graded by your TA
• First lab This week
• Projects take some time because youre learning.

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Recitation

• Led by TA
• Test
• TA will explain details.
• Bring questions.

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Office Hours

• David Dagon
• TBA
• Dan Lerner
• TBA
• David Smith
• Tues Thurs 100 - 300 p.m. or by appointment
• Monica Sweat
• TBA
• Take advantage!!!

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Help Sessions

• Led by TAs or instructors
• Offered for you and driven by your questions.
• Take advantage early
• Not to do your homework for you!

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Resources

• Book
• How To Design Programs
• Felleisen, Findler, Flatt, Krishnamurthi
• http//www.htdp.org
• Class Web Site
• http//www.cc.gatech.edu/AY2002/CS1321
• Lecture slides
• Examples
• On-line Lab Manual
• And much more
• Scheme Web Site
• http//www.cs.rice.edu/CS/PLT/packages/drscheme

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Course Text
How to Design Programs Matthias Felleisen
Robert Bruce Findler Matthew Flatt Shriram
Krishnamurthi ISBN 0-262-06218-6 Also
available at http//www.htdp.org
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WebWork

• Comprehensive package that will be used for
• Announcements
• Discussions
• Assignment Retrieval and Turn in
• etc.
• New version
• Everyone Instructors/TAs/Administrators/Yall
  is still learning this thing
• Your patience and understanding will be
  appreciated

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WebWork

• Available at
• Class web page
• NOT AVAILABLE UNTIL MONDAY!!!
• Username GT Number
• Initial Password Social Security Number
• It might not work!

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Help

• Follow the following sequence of people
• TA (or newsgroup)
• Senior TA (STA) your TA's supervisor
• Instructor/Program Manager

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Our Roles

• Your role
• You are required to demonstrate that you have
  learned this material.
• You have hired us as trainers to assist you.
• You are ultimately responsible for learning.

• Our role
• We will supply you with a variety of resources to
  enable you to learn effectively.
• We will evaluate your performance.
• This evaluation will be part of your permanent
  record.

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Cafeteria Approach

• Resources are available.
• You pick the ones you want to use.
• Evaluation is like the cash register at the end.
• In this case, evaluation is ongoing so you dont
  get a nasty surprise at the end.

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Evaluation

• Homeworks
• Turned in electronically, graded by TAs
• Tests
• Taken in Recitation, graded by TAs
• Lab projects
• Turned in electronically, graded by TA's
• Lecture Final (Official)

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Schedule This Week

• Go to lecture (Tuesday Thursday)
• Go to Recitation (See your schedule)
• Make sure you have a GT Account
• Buy book, start reading

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How the course works
Sun
Mon
Thu
Wed
Tue
Sat
Fri
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You are here
Sun
Mon
Thu
Wed
Tue
Sat
Fri
You are here
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There will be lecture Tuesdays and Thursdays
Sun
Mon
Thu
Wed
Tue
Sat
Fri
You are here
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You will have recitation Tuesday or Wednesday or
Thursday
Sun
Mon
Thu
Wed
Tue
Sat
Fri
You are here
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There is no scheduled Lab time
Sun
Mon
Thu
Wed
Tue
Sat
Fri
You are here
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Homework will be assigned in lecture. It will be
available electronically.
Sun
Mon
Thu
Wed
Tue
Sat
Fri
You are here
HW Assigned
HW Assigned
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Homework will then be due at the midnight before
the next lecture
Sun
Mon
Thu
Wed
Tue
Sat
Fri
You are here
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First Assignment

• Assigned today
• Turn in on paper in class Thursday

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Tests given in recitation. They will cover the
material from the previous homeworks
Sun
Mon
Thu
Wed
Tue
Sat
Fri
HW Due
HW Due
TEST
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Questions?
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Buzzback

• Mandatory survey tool
• Counts towards grade
• We need and want your feedback.
• This course has been heavily influenced by
  Buzzback
• Totally anonymous
• Details later.

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TA Office Hours

• Your TA will announce his/her office hours in
  recitation
• Held weekly
• Get back homework and quizzes
• Discuss problems
• You must at least go to pick up your work
• If the grade is not 100,
• Find out what you missed
• Correct your study habits / procedures

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Grading

• Tests 33
• Homework 20
• Labs 15
• Final 30
• Buzzback complete all 2
• Final gt Tests Final replaces test score
• No curve

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Personnel

• You will have
• A lecturer
• TA
• A senior TA (STA)
• A Program Manager (progmgr_at_cc)

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Is 1321 The Shaft

• The course requires a lot of work.
• We bend over backwards to be fair.
• For many students it is a rude awakening from
  their carefree high school years.
• Some students wait until it is too late to
  realize that they are locked in a death spiral.
• Resources are there to be used. Make use of
  them!!!
• There is absolutely no mandate to run a
  weed-out course.

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Questions?
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Why Me?

• Why everyone should learn to program
• And as imagination bodies forth
• The forms of things to unknown, and the poet's
  pen
• Turns them to shapes, and gives to airy nothing
• A local habitation and a name.
• William Shakespeare
• A Midsummer Night's Dream
• Key words
• Things in your imagination
• Turn them into shapes
• patterns or designs
• Give them a habitation and a name
• executable instances of your ideas

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The Algorithmic Model

• What is Computer Science
• What is Programming
• Algorithms
• Defined
• Properties of Good Algorithms
• Describing Algorithms
• Examples

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Definitions
Computer science is the study of what computers
do.
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Definitions
Computer science, today more accurately a
separate discipline, considers a number of rather
mathematical topics. In addition to computability
questions arising from many problems in discrete
mathematics, and logic questions related to
recursion theory, one must consider scheduling
questions, stochastic models, and so on.
Computer Science is no more about computers
than astronomy is about telescopes.
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Definitions
"Computer Science is, simply put, the study of
computation. The study of anything that lends
itself to a computational model is a study in
Computer Science."
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Definitions
Computer science revolves around computational
processes, which are also called information
processes or simply processes. A process is a
dynamic succession of eventsa happening.
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ProcessWhat?
?
If we define CS based on a study of
computational processes--- Whats a
process?
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A Definition Through Indirection
Another way of describing a process is "a
procedure in execution." A procedure is a
collection of instructions, that results in some
useful behavior on behalf of the device that
executes the instruction. When expressed in a
symbolic language, the procedure is called a
computer program.
What's a procedure?
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What is an Algorithm?
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Algorithms

• An algorithm is a precise method of solving a
  problem
• A given problem may be solvable by a number of
  different algorithms
• An algorithm will typically use levels of
  abstraction to make the solution clearer and
  implementation easier.

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Once upon a time

• Many years ago programmers realized that
  programming a complex task would be simpler if
  they could break the big job down into pieces

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Once upon a time

• This was the birth of modular programming where
  big programs get broken down into smaller pieces
  called modules, methods, subroutines, procedures
  or functions.

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Abstraction

• This breaking down a problem into components that
  finally just do one thing is the key to good
  abstraction.

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Algorithms Abstraction

• A key feature of a well written algorithm will be
  proper use of abstraction
• This will provide an algorithm that
• is more understandable
• is easier to implement and test
• provides more reusable modules
• will get a higher grade!

A
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Why Study Computer Science?
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Myth
Computer science is for techno geeks who want to
drive expensive luxury imports.
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What is Programming

• Programming requires two skills
• Algorithmic thinking
• Knowledge of programming language syntax
• Learning language syntax is the easy part

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Algorithm Defined

• A set of logical steps to accomplish a task
• One way to solve a problem
• A recipe of action
• A way of describing behavior

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Algorithms in Computing
Input Data Algorithm Output Data
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Algorithm Recipe

• Chocolate Chip Cookies DATA
  (ingredients) 2 1/4 cups flour 1 tsp salt 1
  tsp baking soda 2 eggs 3/4 cup brown sugar 1
  tsp vanilla ext. 3/4 cup grand sugar 1 cup
  soft butter 12oz. semi-sweet chocolate
  chipsINSTRUCTIONS (steps) Preheat oven to
  375. Combine flour, salt, baking soda, in
  bowl, set mixture aside. Combine sugars,
  butter, vanilla, beat until creamy. Add eggs
  and beat. Add dry mixture and mix well.
  Stir in chocolate chips Drop mixture by
  teaspoons onto ungreased cookie sheet Bake 8
  to 10 minutes

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Abstraction

• a general idea or term
• an impractical idea visionary and unrealistic
• general characteristics apart from concrete
  realities, specific objects or actual instances
• withdrawal
• absent-mindedness inattention
• a work of art stressing formal relationships

(Random House Dictionary of the English Language)
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Abstraction in Computing

• Refers to the logical grouping of concepts or
  objects
• Define/implement the general idea
• Isolate the details
• Helps readability and understandingof our
  algorithms

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Abstraction in Algorithms

• The Abstraction
• Get to the College of Computing at Georgia
  Tech
• One Implementation
• begin
• get on I-85 heading towards Midtown Atlanta
• exit I-85 at the 10th street exit
• proceed along exit ramp to 10th street
• turn west on 10th street
• turn left on Atlantic Drive
• stop in front of CoC building
• end
• Other implementations of the same abstraction can
  be just as correct, better, or worse

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Why do we stress abstraction?
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Whats Wrong With This Algorithm?
(From back of shampoo bottle) Directions
Wet Hair Apply a small amount of shampoo
Lather Rinse Repeat
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Program Design

• Analyze a problem statement (word problem)
• Express its essence, abstractly and with examples
• Formulate statements and comments in a precise
  language
• Evaluate and revise these activities in the light
  of checks and tests
• Pay attention to detail

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Five Points of Advice by Matthias Felleisen

• You cannot learn everything you need to know in
  lectures and/or homeworks. You must
• 1. Read the Lectures Notes and the Books (How to
  Design Programs)
• Try to stay ahead of the game and read material
  before it is covered in class. If you have
  questions, write them down. If these questions
  don't get covered, ask in class and/or meet with
  the TA, or professor.

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Five Points of Advice by Matthias Felleisen

• You cannot learn everything you need to know in
  lectures and/or homeworks. You must
• 2. Attempt to solve additional problems.
• Try to solve as many exercises as you read
  sections from the book. If you can't do them,
  read the material again.

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Five Points of Advice by Matthias Felleisen

• You cannot learn everything you need to know in
  lectures and/or homeworks. You must
• 3. Attend the lecture and recitations.
• Every professor has a personal understanding of a
  (introductory) course and teaches the material
  according to a personal style. It is important to
  get used to and to exploit this "personalization
  of courses" otherwise, you're wasting your
  money.
• The labs and recitations cover the practical
  know-how (how to edit, how to evaluate, how to
  print, etc.) and illustrate the material from a
  different angle.

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Five Points of Advice by Matthias Felleisen

• You cannot learn everything you need to know in
  lectures and/or homeworks. You must
• 4. Talk to the teachers.
• If the lecture and the notes leave you with
  questions on the material, see your teacher(s)
  during office hours or make an appointment. Mark
  the passages in the book(s) that you haven't
  understood and prepare questions that express
  what you haven't understood.

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Five Points of Advice by Matthias Felleisen

• You cannot learn everything you need to know in
  lectures and/or homeworks. You must
• 5. Keep up.
• Experience proves that students who fall behind
  quickly drop out. So, keep up with the readings,
  tutorials, and the homeworks. Ask for additional
  problems, if the homeworks failed to make a
  point.

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Some Tips

• For many students this will be your first
  exposure to Computer Science (unlike Math,
  Chemistry, etc.)

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Tip 1
Dont wait until the last minute to get help
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Tip 2
Hey, can I still pass if I can get enough partial
credit?
Bad things happen while learning a new skill.
You will probably crash and burn on some
programs. Start early give yourself time for
mistakes.
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Tip 3
Dont be too ambitious with your course load.
You CANNOT slack off in this class, even for a
few days.
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Tip 4
Watch out for the big picture. Dont forget
this is a programming course, not a Scheme
course. Its dangerous to hide from the
programming part of the course. You may be
crushed on the final.
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Discussion?
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