Welcome%20to%20IIT%20and%20cs105!

1
Welcome to IIT and cs105!
2
CS 105 - Sec. 02 Summer 2015

• George Koutsogiannakis office 112 SB
• 312-567-5288
• koutsogiannakis_at_iit.edu
• Best way to communicate with me outside of class
  is via email or
• In my office after class 12 noon-100p.m. T
  Th.
• Course web site
• www.cs.iit.edu/cs105

3

• Lecture/Lab T,R
• 500 P.M. 800 P.M. SB 108

4
CS Intro Courses

• CS 105 1-Semester Requiring Little or No
  Previous Programming Experience, Programming in
  C
• The course covers programming fundamentals.
  Practice exercises are assigned.

5
CS 105 Required Textbook and Lab Manual

• CProgramming From Problem Analysis to Program
  Design By D.S. Malik,
• 5th (red) Edition
• You can use other editions but note that the
  schedule of assignments is based on the 5th
  edition (page numbers differ from edition to
  edition)

6
CS 105 - Quizzes/Exams Grading

• 2 Quizzes Each 5 of Grade
• 2 Exams
• Exam I - Lecture Exam - 10
• Exam II - Lecture Exam - 25
• Final Exam - 35
• Labs - 20
• Must Take Final to Pass Course

7
CS105 Labs

• 11 Labs Assigned consist of
• Reading Assignment, and Lab Exercises from
  Textbook.
• Programming Exercises (Located at End of Each
  Chapter in Textbook)
• Labs Due on specific dates as mentioned on the
  web site.
• Must be present in order to receive credit!
  Points are subtracted if late for lab session.
• Show answers to instructor to receive credit.
• Grades are posted on Blackboard.
• Labs 0-9 1.8 points each
• Lab 10 2 points
• Total 20 points towards your final grade.

8
Lab Grading procedure

1. Start lab on assigned date in class when the
   instructor finishes the lecture part.
2. Ask questions about the lab.
3. Finish lab at home if not completed during the
   class session.
4. Have your lab graded by the instructor on the
   next session by showing your work. You will
   receive a grade when you show your work.
5. The grade will be available on Blackboard.

9
Other Class Work

• I will have practice exercises for you to do on
  the computer during lectures.
• You are required to do the practice exercise and
  not work on anything else!!!!
• No grading for practice exercises.
• Cover topics discussed in order to provide hands
  on understanding.

10
Exams

• 2 quizes 5 points each
• Exam 1 10 points
• Exam 2 25 points
• Exam 3 35 points
• Consist of
• questions about topics discussed
• Small programs
• Hand written.

11
Expectations

• Attendance in Lectures and Labs
• Take notes during lectures!
• Completion of Quizzes and Exams
• Four to Six Hours per Week on Homework
• No Cheating
• Have fun!!

12
Rules

• No Swearing or Other Inconsiderate Behavior
• Turn Off Cell Phones during lectures.
• Questions, Discussion, Ideas Welcome.
• No cell phones, no other material allowed on the
  desk during quizzes or exams.

13
Excuses

• Exam, Quiz Dates Already Posted. No make ups
  except in case of emergency.
• If Emergency
• Doctor/Hospital Note

14
Unacceptable Excuses

• Slept Late
• Felt Sick
• Im Just a Freshman
• Roommate Ate My Alarm Clock/Textbook/Underwear
• Missed Bus
• Had a Game/Match/Practice
• Didnt Know When Exam/Quiz Was
• If Any of Above Happen, Get to Class As SOON as
  Possible!!!

15
CS 105 - Ethics

• Exams
• Closed Book, Closed Notes, Closed Everything
• Nothing in Ears (mp3 players, cell phones,
  etc.)
• Labs Should Be Done Independently

16
CS 105 Where to Get Help

• www.cs.iit.edu/cs105
• Internet Search for C tutorial, or C
  help
• GET HELP EARLY RATHER THAN LATER!!!

17
CS 105 Web Page

• http//www.cs.iit.edu/cs105
• Click on Syllabus
• Weekly Assignments
• Quiz and Exam Dates
• Lecture Slides
• Other Course Information

18
CS105 Labs (Cont)

• All Labs Assigned from Textbook (Malik)
• Work on Labs on Personal PC, or Campus Computers
• Save .cpp File(s) to Floppy or flash drive, or
  send to yourself in email and Bring to Lab
  Section for Discussion and Questions

19
Course Philosophy

• Computer Science Side
• Problem Solving
• Logical Thought
• Programming in C
• Real World Side
• Human Nature
• Corporate World
• Surviving during and after College

20
Problem Solving

• Arrange a Deck of Cards by Suit and Rank
• How Would You Do This?
• How Would You Tell a Child to Do This?
• How Would You Tell a Computer to Do This?

21
Problem Solving

• CS 105 Develops Logic Skills to Solve Problems by
  Writing a Program
• A Program is a Problem Solving Tool
• Computers Follow Instructions Given to Them
• Computers Do Not Have Intuition
• Computers Do Not Make Decisions on Their Own

22
Why Use a Program?

• Computers Perform Tasks Many Times Faster than a
  Person
• Computers Are More Consistent than a Person
• Computers Can Work 24-7

23
Terminology

• Source Code the Original Problem-Solving,
  Logical Solution Written in a Programming
  Language (e.g. C)
• Compiling the Action of Turning the Source Code
  into a Format the Computer Can Use
• Linking the Action of Bringing in Already
  Written Code (Libraries) for Use in a New Program
• Executable the Result of Compiling and Linking a
  Source Program the .exe file that the Computer
  Can Run

24
Terminalogy

• Pseudocode Writing your thoughts for solving the
  problem (the program) in a combination of English
  sentences and programming (i..e C)
  instructions.
• Could take many attempts before the solution make
  sense.

25
Syntax

• A programming language has
• Definite rules as to how to write instructions
  called the Grammar and Syntax of the
  language. Pretty much like a spoken language.
• Has definite words and symbols that make up the
  instructions called keywords. Pretty much like
  the dictionary of a spoken language.

26
C Required Elements

• Every C Program Must Have
• int
• main()

27
Explanation

• In the previous slide
• int , main are keywords.
• (), , are symbols
• How the keywords and the symbols appear in our
  programm, is guided by the grammar/syntax of the
  language .
• i.e. the syntax requires that every C program
  start with the keyword int followed by the
  keyword main followed by ().

28
Explanation

• The symbol indicates that the programming
  instructions start after the symbol.
• The symbol indicates the end of the programming
  instructions.
• The keyword main () indicates the name of a
  function (by the name main ).
• function is a term used to describe a specific
  task that a program has to perform.

29
Explanation

• A program can have many tasks, therefore many
  functions.
• The Grammatical rule that we have learned so far
  is that
• EVERY C PROGRAM MUST HAVE A FUNCTION CALLED
  main
• AND THAT THE SYMBOLS () MEAN FUNCTION
• AND THAT THE INSTRUCTIONS FOR THE FUNCTION
  (TASK) START AFTER THE SYMBOL AND END WITH THE
  SYMBOL

30
How the program is understood by the computer

• A computer understands machine level instructions
  which consist of a series of 1 and 0.
• In other words machine level instructions are
  coded instructions.

31
How the program is understood by the computer

• The program that we write has to
• Be checked for compliance to the grammar and
  syntax of the language.
• Be converted to machine level instructions.
• A software tool called the compiler is
  responsible for the above two tasks.

32
How the program is understood by the computer

• If the compiler finds errors (the first task of
  the compiler)
• It provides you with messages and clues as to the
  kind of grammatical or syntactical errors found.
• It refuses to perform the second task (the
  translation to machine coded instructions), until
  all errors are corrected.

33
How the program is understood by the computer

• After you correct all errors the compiler will
  perform the second task
• You know that the second task of the compiler was
  performed because it produces the executable file
  (the file with the coded machine level
  instructions).
• Clicking on the executable file will cause the
  computer to execute the machine level
  instructions generated by the compiler based on
  your C level instructions.

34
Logical tasks

• Is my program performing the tasks I intended for
  it?
• Note A compiler can not check for logical
  errors only grammatical and syntactical errors
  are checked.
• i.e. suppose the correct logic in the task that
  you want the computer to perform requires the
  addition of two numbers but instead your
  instruction is to multiply the two numbers.

35
Your First Program

• // George Koutsogiannakis
• // CS105
• // Summer Section 2
• include ltiostreamgt
• using namespace std
• int
• main()
• cout ltlt Hello World!! ltlt endl
• return (0)

36
Your First Program

• Notice that certain information about who wrote
  the program, the class the person attends and the
  section number as well as the date are in written
  as comments.
• Same information must appear in every program you
  write in this class as part of the labs or
  exams/quizzes!!!
• Comments are disregarded by the compiler and they
  are marked with // in each line.

37
Writing a C Program

• Write Pseudocode (Design)
• Translate Pseudocode into C Source Code in
  Visual C
• Edit Code
• Compile
• Link

38
What Is Pseudocode?

• Every Programmers Way of Writing Down Steps in
  Solving a Problem
• Steps in Creating Pseudocode
• Understand the Problem
• Decide How to Solve the Problem
• Write the Solution Using a Logical Sequence of
  Statements
• Design Issues Apply to almost ANY Vocation

39
Writing Source Code

• Source Code Is the Actual Program Code that Will
  Run Once Compiled and Linked
• Pseudo Code Should Be Easily Translated into
  Source Code

40
Preprocessing

• Preprocessing Is the Actions Taken Before a
  Source File Is Handed Off to the Compiler
• Outcome of Preprocessing Must Still Be a Correct
  Source Code File
• Example Preprocessing Statement
• include Includes Text of Other Source Files
• include Usually Occur at Top of Program
• Pound Sign () Must Be in First Position on Line
• Example include ltiostreamgt for Typical Input
  and Output Operations in C

41
Compiler

• Converts Source Code into an Object File or
  Machine Code
• Each Change to Source File Requires a
  Recompilation
• Compiler Detects Syntax Errors
• Syntax Error a Non-Proper, Not Allowable,
  Sequence of Characters or Words Given a
  Particular Language

42
Syntax Errors

• Spelling Errors Examples
• Undefined Variable Name
• Unrecognized Keyword
• Cannot Find Include File or Library
• Punctuation Errors Examples
• Missing Curly Braces
• Missing Semicolons
• Malformed Comments
• Syntax Errors Are Listed at Bottom of Screen When
  Compilation Is Complete

43
Syntax Errors (Cont)

• Syntax Errors Are Listed at Bottom of Screen When
  Compilation Is Completed
• Two Kinds of Messages
• Warning Compiler Thinks There Is a Problem, but
  Lets It Go By Without Failing
• Error Compiler Finds an Error and Fails to
  Compile
• First Error in Program May Cause Other Errors
  to Show Up
• General Rule Fix First Error (and Any Obvious
  Errors) Then Recompile

44
Linking

• Links (Connects) Object Code with External
  Libraries, which Contain Functions (Already
  Written and Compiled Code) to Use with Another
  Program
• Creates an Executable File
• An Executable File (e.g. .exe File) Can Be Run
• If Linker Cannot Find Libraries, Error Message
  Are Generated

45
Logic Errors Bugs

• Also Called Semantic or Run-Time Errors
• Program Compiles, but Doesnt Produce the
  Expected Results
• Examples
• Program Keeps Running Forever (Infinite Loop)
• Nothing Happens
• Program Output Is Incorrect
• Error Message at Run Time (e.g. Dividing by 0)
• Errors May Be Intermittent
• May Be Able to Find Semantic Problems with
  Debugger

46
Detecting Bugs

• Running Program Should Be Tested Several Times
  with Different Inputs
• Test Plan Series of tests (e.g., inputs) that
  have predetermined expected outputs.
• Running Program Should Be Tested Several Times
  under All Potential Conditions
• When Errors Detected Analysis Needed Debugging
  Mechanism

47
Comments

• Comments Describe a Program
• // Comment to end of line
• / Comment until first occurrence of star slash
  /
• Difficult to Understate Importance of Good
  Comments
• Should Be at Beginning of Program (Overall
  Summary)
• Should Be Next to Variable Declaration Briefly
  Describing Uses of Variable
• Should Be Anywhere in Program Where Unobvious
  Coding Is Performed

48
Program Format

• White Space
• Not Recognized by Compiler
• Indent (e.g. 3 Spaces) for Each New Function,
  Selection, or Loop

49
Variables

• Identifiers Used to Store Values that May Change
• Every Variable Has a Type What Kind of Value
  (e.g., Integer, Floating Point Number, Character)
  Is Begin Stored
• Every Variable Has a Value which Is Assigned and
  Can Be Changed
• Every Variable Must Be Declared, which Sets Aside
  Memory for the Storage Location

50
Declaring a Variable

• Declaration Normally Comes after a Function
  Definition Opening Curly Brace int main()
  
• int num1 //variable
  declaration
• num1 10 // variable assignment
• cout ltlt num1 // variable output
• Declaration Includes Type and the Name of the
  Variable
• All Variables Must Be Declared before Being Used

51
Variables and Main Memory
Main Memory

• int num
• num 10
• num 15

num
ltgarbagegt
num
10
num
15
52
Main Memory

• Storage Location of Data in a Computer
• Used When a Program Is Running
• Wiped Clean When Computer Rebooted
• Bit a logical single 1 or 0 value (sometimes
  referred to as True or False)
• Byte Basic Unit of Storage (Can Store One Letter
  of the Alphabet)
• Consists of 8 Bits.
• Kilobyte (KB) 1000 (or 1024) Bytes (Pages of
  Text)
• Megabyte (MB) 1,000,000 Bytes (Large Pictures)
• Gigabyte (GB) 1,000,000,000 Bytes (Music Files,
  Video Files)

53
Initialization and Assignment

• Initialization Value Given to Variable at
  Declaration
• Assignment Value Given to Variable in Execution
  Statement

54
Variable Initialization

• int main()
• int num1 10 //variable
  declaration
• // with initialization
• cout ltlt num1 // variable output

55
Built-In (or Primitive) Data Types for Variables

• int Integer Range of Typically -32,768 to 32,767
  (machine and compiler dependent)
• float Real Number (i.e., integer part, decimal
  part, and exponent part) Range of Typically
  10e-38 to 10e38
• double Larger Real Number (10e-308 to 10e308)
• char Character

56
Naming Variables in C Identifiers

• Can Use Letters Remember That C is Case
  Sensitive (e.g., NumWidgets Is Not the Same as
  numwidgets)
• Can Use Digits 0-9, and Underscore
• Cannot Start with a Digit
• Cannot Contain Spaces or Other Characters
• Typically Maximum of 32 Characters
• Cannot Use C Keywords

57
Naming Variables (Cont)

• Should Use a Meaningful, Descriptive Name so that
  Variables Use Is Easily Understood
• Examples
• counter, second, minute, length, width
• Be Consistent with Case Usually Lower Case with
  Upper Case for Second Part of Variable Name
• Examples
• averageRainfall, totalStudentGrades,
  maxBuildingHeight, minPackageWeight

58
Variable Scope

• Scope Area of a Program within which a Variable
  Can Be Referenced
• Variable Definitions Are Recognized in the Curly
  Braces in which They Were Defined
• Variables Declared Outside of Functions Are
  Recognized from the Point Declaration through the
  Rest of the Program

59
Named Constants

• Constant An Identifier that Is Initialized to a
  Value that Cannot Change
• Usually Declared at Top of Program using Keyword
  const
• Standard Naming of Constants Is to Use All Upper
  Case Letter with or without Underscore between
  Words
• All Constants Must Be Initialized
• Syntax const int MAXHT 100

60
Advantages of Constants

• Easier to Understand
• Easier to Modify
• Example Compare using Number 5000 in Program
  versus Constant MAXHT

61
Named Constants

• const int MAXHT 100
• main()
• ...
• currentHeight gt MAXHT
• ...
• bridgeHeight MAXHT
• ...
• bridgeHeight newAddition gt MAXHT
• ... // used MAXHT 223 times in this program

62
Literal Constants (Values)

• Constants Whose values Are Already Known
• Characters (Specified Inside Single Quotes)
• A , a , 5 , , \n (newline) , \0
  (NULL Character)
• Integers
• 10, 1345, -34
• Float or Double
• 2.3, -45.18, 10.6e6
• String (Specified Inside Double Quotes)
• HELLO , What a great deal. , 5

63
Input and Output

• Also Known as I/O
• Output Stream cout ltlt variable
• Input Stream cin gtgt variable
• New Line endl
• All C Statements End in Semicolon ()

64
Input and Output Example

• include ltiostreamgt
• using namespace std
• int
• main()
• int numEntered
• cout ltlt Please enter an integer
• cin gtgt numEntered
• cout ltlt Thanks, you entered ltlt numEntered
  ltlt . ltlt endl

65
Characters and Strings

• Standard Template Library (STL) Library of C
  Functions Used Worldwide
• String Type NOT Built-in in C
• String Type Defined in STL
• To Use STL Strings
• include ltiostreamgt
• include ltstringgt
• using namespace std
• string lastName

66
STL Strings

• Declaration string yourName
• Assigning a Value to a String
• yourName A. Goose
• String Constants (Values) Must Be Enclosed in
  Double Quotes

67
Input String Example

• include ltiostreamgt
• include ltstringgt
• using namespace std
• int
• main()
• string lastName
• cout ltlt Enter your last name
• cin gtgt lastName
• cout ltlt Your last name is ltlt lastName
  ltlt endl
• return(0)

68
Expressions

• Expression A Sequence of One or More Identifiers
  and Operators that Evaluates to a Value
• Operator A Symbol Expressing a Way to Modify a
  Value or Values (e.g., for Addition)
• Operand A Value Being Modified by an Operator
• Example Expressions
• 5
• currentHeight
• currentHeight 10

69
Arithmetic Expressions

• Standard Arithmetic Operations Can Be Performed
  Addition, Subtraction, Multiplication, Division
• Standard Arithmetic Operators Can Be Used for
  These Operations , -, , /
• Others
• - Modulo (Mod) Remainder after Integer
  Division
• -- Decrement (Subtract 1)
• Increment (Add 1)

70
Order of Operations

• Precedence Level of Importance of Operations
• Multiplicative Operators Have Higher Precedence
  than Additive Operators
• , /, Higher
• , - Lower
• Associativity Order of Operation for Equal Level
  Precedence
• Most Operators Have Left-to-Right Associativity
• Use Parentheses to Force Differing Precedence of
  Operations

71
Know for the Quiz 1- July 07

• All Terms (Underlined Items)
• Variable Declaration, Initialization, and
  Assignment
• Constant Declaration
• Expressions
• Operators
• Input (cin) and Output (cout)

72
Know for the Quiz

• Read Chapters 1 2 , pages 28-67, 67-77, 77-86,
  86-100, 117-124. (Note Edition 5 page numbers)
• Ask questions about the exercises if unable to
  complete Lab 0 OR Lab 1.
• Practice with additional exercises from text on
  your own.
• Study examples material distributed in class.
• Study Lect 01, 02, 03 slides. Also study the
  first 3 slides of Lect 04, 05
• Quiz will be given at the end of class period,
  after the lecture part.

73
Quiz Format

• 15 questions where you are given a concept and
  you are asked to match it against a list of
  definitions (3/5 of the grade).
• Write one program (2/5 of the grade) that
  requires
• Declarations of constants and variables.
• Input from user.
• Arithmetic expressions including increment or
  decrement operators.
• Display of program output