CS 2130

1
CS 2130

• Lecture 2
• Academic Misconduct
• More Overview History
• Some C Stuff

2
Policy Reminders

• No Cell phones/Beepers/Alarms
• Be considerate of others. Be on time.
• No whispering
• Buzzcard required to take exams
• Policies posted on
• Class newsgroups
• git.cc.class.cs2130.announce
• Class Co-Web
• http//swiki.cc.gatech.edu8080/cs2130

3
New Institute Policies!

• Effective Fall semester, 2001
• Graduating seniors take the final exam during
  finals week
• Mid-semester grade reports for all 1000 and 2000
  level classes
• Satisfactory/Unsatisfactory grade (non-binding)
• Issued after Fall Break (on or about Oct 17)
• After Drop Day!
• Students with unsatisfactory performance will be
  encouraged to meet with TA or Instructor

4
Academic Honesty

• It is expected that (unless specific instructions
  to the contrary are given) all student
  submissions will be individual efforts.
• All required coursework that is submitted for
  evaluation in this academic course becomes the
  property of the Georgia Institute of Technology,
  and is subject to review for evidence of academic
  misconduct. If such evidence is discovered,
  then the offending students will be referred to
  the Dean of Students for investigation.

5
Academic Misconduct

• Section XVIII.C. of the Student Rules and
  Regulations defines academic misconduct as "any
  act that does or could improperly distort student
  grades or other student records."
• Among the list of items that are cited in this
  section are the following

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Academic Misconduct

• 1. Possessing, using or exchanging improperly
  acquired written or verbal information in the
  preparation of an essay, laboratory report,
  examination, or other assignment included in the
  academic course.
• 3. Submission of material that is wholly or
  substantially identical to that created or
  published by another person or persons, without
  adequate credit notations indicating the
  authorship (plagiarism).

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Academic Honesty

• In layman's terms, this means that if any student
  receives or provides any information that would
  enable himself/herself or any other person to
  complete an assignment or examination that is not
  wholly the work of the person submitting that
  assignment or examination, then that student is
  in violation of the academic honor code of
  Georgia Tech. This includes copying published
  material from any source, whether written or
  electronic.

8
Academic Honesty

• To prevent problems in this area, make sure that
  all assignment solutions that you submit are
  properly cited (this includes homeworks). If you
  copied the answer from a book ("any" book), then
  cite it. If you got the information from a web
  page, then cite it. If you got it from your class
  notes, then cite it. As long as appropriate
  citations are given, then the worst thing that
  will happen to you if you copy from an
  "unapproved" source is that you will get a 0
  (ZERO) on the assignment. If you copy material
  and do not cite it, then you will be reported to
  the Dean of Students on suspicion of academic
  misconduct.

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Academic Honesty

• Any such incidents will be dealt with
  accordingly, and penalties for conviction can be
  severe - up to and including notice of academic
  misconduct on a transcript, failure in the
  academic course, expulsion from the College of
  Computing, expulsion from Georgia Tech, and
  community service.

10
Tests

• Tentative Dates on Syllabus (i.e. subject to
  change, but they usually don't)
• Test 0 Thursday, September 20, 2001
• Test 1 Thursday, November 8, 2001
• Final Exam TBA
• Graduating Seniors must take the Final Exam!

11
Languages Translation

• Natural Languages
• English
• French
• Russian
• Japanese
• Esperanto
• Very complex rules of grammar
• Often ambiguous
• Usually tied to speech
• Constantly evolving
• Often very context sensitive

• Computer Languages
• Assembler
• Fortran, Cobol, Basic
• C, Ada, Forth
• Lisp, Scheme, SML
• Prolog
• Smalltalk, C, Java
• Grammars more structured than natural languages
• Precise?
• Not often spoken
• Fixed by version/standard
• Context free?

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Languages Translation

• Converting one language into another
• We will deal with translation of computer
  languages
• Why do we need translation?
• Efficiency
• Abstraction (Want to write in HLL)

13
A Little History

• Beginnings (30's and 40's)
• Theoretical Foundations of Computer Science
• Turing, Godel, Church, Markov, Post, Kleene
• Binary logic/Idea of algorithms
• First electronic computers in 40's
• Programming by wiring then machine language
• Development of Programming (50's)
• Symbolic names
• Assemblers
• High Level Languages (60's)
• High Level Languages (e.g. Fortran/Cobol)
• Data structures/Parameters
• Transportability?/Program as assembly of parts

C70600000002
MOV X,2
X 2
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A Little More History

• Program Size Complexity Increasing (70's)
• C and Pascal
• Recursion and Dynamic Memory
• Interactivity/Timesharing (80's)
• Software Engineering
• Object Oriented Approach Smalltalk C
• Network Prominance (90's)
• Internet/www
• Separate compilation
• Java
• Next???

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Translation by any other name...

• Compiler
• Translates program written in "source" language
  to "target" language
• Interpreter
• Translate and immediately execute
• Assembler
• Translate into machine language for particular
  machine
• Macro Processor
• Textual substitutions

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Compilers

• Fortran
• .for ? .obj ? .exe
• C
• .c ? .o ? a.out
• Java
• .java ? .class
• Compilation often used for speed and efficiency
  of executable code

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Interpreters

• Emulators
• Basic
• Beginner's All-purpose Symbolic Instruction Code
• Lisp
• Scheme
• Java Virtual Machine
• Interpreters often used for educational/rapid
  prototyping and portability in the case of Java

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Assemblers

• Typically processor/machine specific
• Some compilers produce assembly code
• Very close tie to hardware
• Symbolic version of machine language
• Still used for speed/size in performance critical
  apps
• Needlepoint for nerds?

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Macro Processors

• C Preprocessor
• Performs many useful tasks before "actual"
  compilation begins
• Macro substitutions
• C
• Initially preprocessor translated C program
  into C program
• m4
• UNIX macro processor
• Nobody understands how to use it

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Other Items?

• Linkers
• Loaders
• Editors
• Debuggers
• Profilers
• Project Managers
• Instant Messengers
• Quake
• Jolt/Surge/etc.

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C Programming

• 5 Weeks
• Not a C Programming course
• Focus on using for translation
• C as translation target
• Course designed to be taken at same time as ECE
  2030

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C Review?

• BCPL (Typeless) - 1967 - Operating Systems
• B - Ken Thompson - First version of Unix
• C - 1972 - Dennis Ritchie - Implemented on PDP-11
• Unix rewritten in C in 1974
• Publication of "The C Programming Language" by
  Brian Kernighan and Dennis Ritchie
• ...
• ANSI C (1989)
• Major updates to C standard in 1994 and 1999
• We will use C89 in CS 2130 (GNU C compiler)

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C Stuff

• C Programs generally consist of one or more
  functions
• Execution starts in a function called main
• Arrays
• Start at 0
• No bounds checking
• Strings
• There are no strings...more later!
• Structures
• Like records (or objects where all members are
  public)
• Pointers
• Variable containing an address or location

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More C Stuff

• Comments / /
• Types
• Character
• Integers
• Warning Hex constants...Octal Constants
• Long and Short
• Signed and Unsigned
• Floating Point
• Sizeof
• sizeof(int) / sizeof a type /
• sizeof x / sizeof a data object /

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Expressions

• A constant or variable by itself is an expression
• Combinations of constants and variables with
  operators are also expressions
• Examples
• 7 / Constant /
• x / Variable /
• x 7 / with operator /
• x x 7 / with operators /
• x x 7 / Simple statement /

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Operators

• Assignment Operator Evaluate expression on
  right, store result in variable on the left
• Add value on right side to variable on left
  side
• - Subtract value on right side from variable on
  left side
• Multiply variable on left side by value on
  right side
• Assignment expression itself has a value!
• a b c 0

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Other Operators

• Binary Arithmetic - /
• Unary - --
• Bitwise ltlt gtgt
• Relational lt lt gt gt !
• Logical !

Pretty much the same as Java except there is no
boolean value
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Questions?
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