CS Department Survey

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CS Department Survey

• while waiting for class to start

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Week 01 - a

• Course Introduction
• What is Computer Science?
• What is Programming?
• How Do Computers Work?
• Using the BlueJ IDE

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Course Philosophy
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Sample Programs Referenced(code located in
course folder)

• Simple I/O

• simcom(AnimatedIllustrations)
• Payroll
• Washer Weight(bring washers)
• Temperature Conversion

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Handouts(All are Available on Web)

• Course Schedule
• Grading Policies
• Programming Standards
• HW 1 Temperature Conversion
• HW Grading Sheet
• to be attached to the front of all HW

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Course Introduction

• Web site http//cs.union.edu/csc105
• Students and Instructor
• Goals and Objectives
• Schedule
• Textbooks
• Grading
• Labs
• Assignments

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Typical CSc-105 Student

• Extensive C/Java experience?
• Should be in CSc-140 (Data Structures)
• Some Programming Background?
• CSc-10 or equivalent High School Course
• May have had a little C/Java experience
• No Programming Experience?
• Need to have a logical mind
• good at math, chess, problem solving, etc.
• Youll need to spend extra time on course

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Introductions

• Instructor Dave Hannay
• Please send email to hannayd_at_union.edu
• Your name, class year, major, computer background
• Counts as HW 0 due before next class
• Office in Steinmetz 207 388-6318
• Office Hours
• Mondays 130-245pm
• Wednesdays 930-1100am 130-245pm
• Thursdays 930-1030am
• Others by Appointment
• Or just stop in if you're in the neighborhood
• here most of the day at least 4 days per week

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Obtaining Course Software

• First the good news It is all free!
• Now the bad news It takes a while
• You will need two items on your PC/MAC
• (see course web site for links)
• Java Software Development Kit (not needed for MAC
  OS/X)http//java.sun.com
• BlueJ Integrated Development Environmenthttp//ww
  w.bluej.org

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Course Outline

• Course Schedule
• Reading assignments
• Exam Dates this term
• Test 1 28 Sep 2005
• Test 2 24 Oct 2005
• Final ?? Nov 2005
• Tests
• Tests are "closed book"
• May bring up to 4 (double-sided) sheets of notes
• may not be shared during the test

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Textbooks

• Problem Solving with Java, 2nd Edition (Addison
  Wesley, 2002)
• by Elliot Koffman Ursula Wolz
• BlueJ Tutorial (download at www.BlueJ.org)by
  Michael Kölling

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Course Logistics

• Class runs from 300 440pm
• 5 minute break around 350
• Grab a cuppa java -or-
• Get help on reading/lecture material -or-
• Demonstrate or get help on HW
• Bring Textbook with you to Class Lab
• For In-Class Exercises
• As a Command Code Reference

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Grading
see Grading Policies Web Page for Attendance
Policy

• 25 Test 1
• 25 Test 2
• 30 Test 3 (Final)
• 10 Homework Projects
• 10 Lab see Grading Policies Web Page for
  Rules

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Laboratory

• Hands-on Practice
• Bring Textbook (needed as reference)
• Olin 110 (use ID Card for access)
• You may work there at other times if there is no
  class meeting at the time
• You should have been assigned to either Morning
  (1050am) or Afternoon (145pm) Lab Tomorrow

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Programming Assignments

• Really worth 100 since doing them will affect
  your performance on Tests Labs as well
• List names of all people working with you or from
  whom you received any assistance (assisted by)
• Extra Credit for doing something significant
  beyond requirements.

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Course Instructor will serve as the "Client"

• After turning in each assignment, you need to
  demonstrate the features of your program to the
  client
• HW not graded until after the demonstration
• Demo in my office, or before class

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Programming Assignments

• The purpose of the HW exercises is not merely to
  parrot back things that you learn in class, but
  rather to learn by doing.
• As I can assure you from years of programming
  experience, you learn a lot more about writing
  programs by trying things that sometimes don't
  work than by simply copying someone elses
  working code.

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Experience is the Best Teacher!

• Learning what does not work is as important as
  learning what does work
• It will save you a lot of time in the future.

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Turning in Homework

• Create program using BlueJ
• Compile/Run Program
• possibly multiple times
• Print out Program Demonstrate
• Copy contents of Output (Paste into File)
• to show Results
• Staple Grading Sheet to front
• Due at Beginning of Class on Due Date

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What is Computer Science?

• Algorithms Data Structures
• Computer Architecture
• Artificial Intelligence Robotics
• Database Information Retrieval
• Human-Computer Communication

• Numerical Symbolic Computation
• Operating Systems
• Programming Languages
• Software Methodology Engineering
• Social Professional Context

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Algorithms Data Structures

• Specific Classes of Problems and their Efficient
  Solutions
• Performance Characteristics of Algorithms
• Organization of Data relative to Different Access
  Requirements
• (what we do in this class)

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Computer Architecture

• Methods of Organizing Efficient, Reliable
  Computing Systems
• Implementation of Processors, Memory,
  Communications and Software Interfaces
• Design and Control of Large, Reliable
  Computational Systems
• (more on this shortly)

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Artificial Intelligenceand Robotics

• Basic Models of Behavior
• Building (virtual or actual) Machines to Simulate
  Animal or Human Behavior
• Inference, Deduction, Pattern Recognition and
  Knowledge Representation

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Database andInformation Retrieval

• Organizing Information and Designing Algorithms
  for the Efficient Access and Update of Stored
  Information
• Modeling Data Relationships
• Security and Protection of Information in a
  Shared Environment
• Characteristics of External Storage Devices

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Human-Computer Interface

• Efficient Transfer of Information between Humans
  and Machines
• Computer Graphics
• Human Factors that Affect Efficient Interaction
• Organization and Display of Information for
  Effective Utilization by Humans

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Numerical and Symbolic Computation

• General Methods for Efficiently and Accurately
  using Computers to Solve Equations from
  Mathematical Models
• Effectiveness and Efficiency of Various
  Approaches to the Solution of Equations
• Development of High-Quality Mathematical Software
  Packages

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Operating Systems

• Control Mechanisms that Allow Multiple Resources
  to be Efficiently Coordinated during Execution of
  Programs
• Appropriate Service of User Requests
• Effective Strategies for Resource Control
• Effective Organization to Support Distributed
  Computation

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Programming Languages

• Notations for Defining Virtual Machines that
  Execute Algorithms
• Efficient Translation from High-Level Languages
  to Machine Code
• Extension Mechanisms that can be Provided in
  Programming Languages

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Software Methodologyand Engineering

• Specification, Design and Production of Large
  Software Systems
• Principles of Programming and Software
  Development, Verification and Validation of
  Software
• Specification and Production of Software Systems
  that are Safe, Secure, Reliable and Dependable

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Social andProfessional Context

• Privacy and Misuse of Data
• Hacking and Viruses
• Plagiarism and Software Piracy
• Misuse of a Computer Resource

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General-PurposeStored-ProgramDigitalComputers
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Computer Architecture

• Central-Processing Unit
• performs the actual work of executing the program
• Main Memory
• holds the program and during execution
• Hard Disk (secondary storage)
• holds all programs not executing and all data
  files
• Input/Output Devices
• allow the computer to communicate with the
  outside world

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Input/Output I ? NY

• (credited to Roger Hulls brother-in-law, John
  Dyson, while he was NYS Commissioner of Commerce)
• public class SimpleIO
• public void Love() throws java.io.IOException
• System.out.print("Please enter state ")
• char ch1 (char) System.in.read()
• char ch2 (char) System.in.read()
• System.out.println("I LOVE " ch1 ch2)
• // end of Love method
• // end of SimpleIO class
• Try Maine!

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Binary

• Computers use Binary Numbers
• bit binary digit
• byte collection of 8 bits
• word usually 4 or 8 bytes (32 or 64 bits)

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Data Representation

• Numbers can be used to represent any type of data
• Each text character is assigned a unique number
• ASCII uses 1 byte (8 bits 256 possible
  characters)
• Unicode uses 2 bytes (16 bits over 65,000
  characters)
• pictures are represented by dividing them into
  picture elements known as pixels
• video images or animations are represented by
  placing several pictures one after another
• songs are represented by sampling the wave at
  regular intervals

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Computer Software

• Operating System
• Examples?
• Responsibilities?
• Application Software
• Examples?
• Where do they reside when not in use?
• Where do they reside when running?

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Programming Languages

• Machine Language
• Binary codes
• Processor specific
• Assembly Language
• Mnemonic codes
• Processor specific
• High-level Language
• English/math-like codes
• A A B
• Processor independent
• Examples of high-level languages?

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Object-Oriented Programming

• Programs are structured as a collection of
  classes.
• Each class describes a type of object.
• A program creates a collection of objects from
  class definitions.
• Objects interact via methods.
• Objects also have attributes that describe their
  state.

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Analogies for Concept of "Class"

• Class Blueprint for houses in Levittown
• Properties (attributes, state) Location, Color,
  etc.
• Object One House (e.g. identity myHouse)
• Constructor Contractor ("Construction" workers)
• Class Class of People (say Union students)
• Properties GPA, major, birthdate, height, etc.
• Object Person in class
• Method person.installLightBulb(b)

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Mike the Monster

• Class Monster
• Class attributes (data)
• Color
• Number of eyes
• Others?
• Class methods
• Speak
• Look left
• Look right
• Others?

• Object Mike
• Object attributes
• Color green
• Number of eyes 1
• object.method
• Mike.speak("Its scaring time!")
• Mike.lookLeft()

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To the Computers...

• Check out the Course Web Site if you havent
  already done so
• cs.union.edu/csc105

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Java BREAK
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Running a Program
Main memory
CPU
Fetch/Execute Cycle
Hard disk
Program
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Running a Program

• First the program and all its data are copied
  from the hard disk into main memory
• The CPU goes to the location of the program
  instruction and reads that word
• The CPU determines what action is requested by
  decoding its bit pattern representation
• The CPU performs the action
• The CPU then moves to the location of the next
  program instruction in memory, reads the word,
  and repeats the process

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"Stored Program" Concept

• Simple Computer Simulation
• PC Start Menu gt Run gt cmd
• set CLASSPATH
• C (to change to drive C)
• cd \AnimatedIllustrations
• java simcom.SimComFrame
• -OR- Double-Click the "MS DOS Command Prompt"
  icon
• File Menu gt Scenarios gt Times5
• Double-Click Decimal Value of Location 31
• Change to 17
• Step Button then Step Lightspeed
• Watch what happens!

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We will use an IDE (Integrated Development
Environment). It contains an editor, compiler,
interpreter, and more!
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Processing a Java Program

• What form must our program instructions be in so
  that they can be executed?
• What do Java instructions look like?
• A compiler is a program that translates source
  code into object code.
• Java is different (Java is also more Fun)
• Why?
• How?

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Software Development

• Specify the problem requirements
• Analyze the problem and identify the classes that
  will be needed
• Design the classes
• Locate relevant existing classes
• Modify existing classes
• Design new classes
• Implement the new and modified classes
• Test and verify the completed program
• Maintain and update the program

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Java Modes

• Applications
• stand-alone programs that run on you own computer
• can read and write data on your hard disk
• Applets
• executed from within a browser window (e.g.
  FireFox, Netscape or Internet Explorer)
• can be loaded from the World Wide Web and
  executed on another computer
• cannot read or write data on your hard disk

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Object-Oriented Programming and Java

• The use of OOP in Java is pervasive
• easy to create multiple objects of the same type
• easy to create similar objects without having to
  rewrite the overlapping code
• OOP makes programs easier to understand and more
  reliable
• Prevents objects from having to know any more
  about structure of other objects than is really
  necessary

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Objectives in Programming

• A program should solve a problem
• correctly (it actually solves the problem)
• efficiently (without wasting time or space)
• readably (understandable by another person)
• in a user-friendly fashion (in a way that is
  easy to use).

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Errors

• Errors found in a program
• Syntactic errors are caused by giving the
  compiler a program it cannot recognize
• Logical errors come from programs that compile
  correctly but fail to execute as expected
  sometimes much harder to find!
• Programs must be designed carefully and tested
  thoroughly to ensure that neither type of error
  will occur

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Testing and Debugging

• These are crucial skills.
• Testing searches for the presence of errors.
• Debugging searches for the source of errors.
• The manifestation of an error may well occur some
  distance from its source.
• Commercial Software is rarely bug free!
• Dilbert has trouble with a software vendor...

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Using BlueJ

• Start BlueJ
• Open Project (Payroll Application)
• Open Class (Payroll)
• Edit the class
• Revise the code from the template
• Compile the class
• Add other classes as needed
• Either instantiate an object and run method or
  run the main method (more on this later)

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Simple Payroll Class

• / CSc-105 In-Class Demonstration "Payroll"
• class Payroll
• Calculate gross pay given hours worked and
  rate of pay
• _at_author Dave Hannay
• _at_version Lecture Week01-a
• /
• public class Payroll
• public void calcPayroll()
• double hours 40.0 // hours worked
• double rate 9.65 // rate of pay
• double pay // gross pay
• pay hours rate
• System.out.print("Hours")
• System.out.print(hours)
• System.out.print(" x Rate")
• System.out.print(rate)
• System.out.print(" PAY ")
• System.out.println(pay)

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Case Study Problem Definition and Analysis

• Problem Get weight of a box of flat washers
• User should enter the washer dimensions, density
  and quantity
• Program should compute and display the weight
• Analysis
• Box weight Quantity Washer weight
• Washer weight Volume Density
• Volume Surface area Thickness
• Surface area area of outer circle area of
  inner circle
• Area of circle PI radius 2

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Case StudyDesign the Classes

• Most solutions will involve at least 2 classes
• Worker class to represent the object being
  modeled
• User interface or Application that interacts
  with the user
• Classes
• Washer ? Worker
• WasherApp ? User Interface or Application
• Others?
• Any existing classes for input and output?
• Washers are circular ? Circle class?

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Classes for Washer Weight
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Class Definitions

• Attributes (data fields) describe state
• e.g. a circle has a radius
• Methods define what the object can do or what can
  be done to an object
• e.g. a circle should be able to compute its area
  and a user or client should be set the circles
  radius
• see Circle class
• What attributes should the Washer class have?
• What methods should the Washer class have?

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Class Definition Form

• Header
• Body
• Data field declarations
• Method definitions

• public class Circle

private double radius
public double computeArea() return Math.PI
radius radius
Review the code for the Circle and Washer
classes(in BlueJ, and on handout)
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HW Assignment 0 and 1email and Temperature
Conversion

• HW 0Send e-mail to hannayd_at_union.edu
• Preferred Name, Class Year, Major
• Computer Background
• Due before next Class
• HW 1Enter and run given program
• Purpose
• Example of Documentation Standards
• Learn how to Print Program Files
• Learn how to e-mail Attachments
• Due One Week from Today

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Lab 1 Pre-Lab

• Read Sections 1.4 and 1.5 in the textbook
• Download the BlueJ Tutorial (see web)
• In general, it is a good idea to read the
  material before it is presented in class so that
  you can be prepared to ask questions when a
  particular topic is discussed.
• HANDOUT How-To Notes

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To the Computers...

• Run the "square" Scenario on simcom
• Double-Click "DOS Command Prompt" Icon, then type
  in
• set CLASSPATH
• java simcom.SimComFrame
• Double-click the second column of location 31 to
  enter number to be squared.

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Java BREAK