Computer Science 1 Lecture 1: administrative details and Professor: Evan Korth New York University 1

Road Map for Today Welcome to Introduction to Computer Science I! Course Description –What material will we cover? –What am I getting myself into? Administrative Issues –Course Web Page, Text Book, Exams, Office Hours, Homework, Grading, Cheating Policy, etc. Syllabus Reading: chapter 1 2

Course Prerequisites Prerequisite: V or departmental permission. Math placement at Calculus I level or higher. Who should be taking this course: –computer science majors or minors –other science students –students who know the basics of some programming language. Who should NOT be taking this course –Students that know Java well (should either go straight to 102 or take the honors section – See me) You must get a c or better in this class to take further computer science classes. 3

Course Description Official Description: Students learn how to design algorithms to solve problems and how to translate these algorithms into working computer programs. Experience is acquired through programming projects in a high level programming language. V is intended as a first course for computer science majors, and for students of other scientific disciplines. 4

What the class is really about There are three main goals of this course: 1. Foundations of Java 2. Foundations Algorithm development 3. Foundations of Software Development 5

1. Foundations of Java Programming Java is a popular programming language, widely used in industry. We will learn all the specifics of how to program in Java. This includes all the peculiar rules that are specific to Java. We will review the fundamentals: Variables, Arithmetic, If / Else, For Loops, While Loops, Arrays, Methods, etc. We will cover object orientated material 6

7 2. Algorithm development We will look at problem solving methods that involve analyzing the problem and designing an algorithm before we start to write code.

Learn the Principles of Software Development Building high quality software is very difficult. The course presents the syntax and concepts of programming, and also presents strategies for building real software that addresses real problems. I will also try to bring my real-world industry experience to class. 8

Administrative Matters 9

Course Web Site Course web site is available at: 004/index.htm Web site contains the following information: –Administrative information –Course Syllabus –Homework assignments –Class notes –Class programs –Sample exams –Compiler instructions –Link to the class mailing list 10

Class mailing list First assignment is to join it. Do it today! Go to: 004_fa03 and follow the instructions All assignments and news will be sent to the class list Homework questions should be sent to the list and answered by students when possible. 11

Course Text Book Introduction to Java Programming (4th Edition) Available at the NYU Bookstore Book includes a CD- ROM with Java programs and other supplemental materials. Lecture notes will follow the book. Please keep up with the reading! 12

Software For the course, we will be using the following software: –Sun’s JDK (Java Development Kit) –The Jcreator IDE (Integrated Development Environment) Both products can be downloaded from the web for free. The class website has instructions on downloading and installing these programs. Please download the compiler as soon as possible. If you do not have your own computer, the computer labs on campus have the software. 13

Grading Your grade will be determined as follows: –Midterm (30%) –Homework (possible quizzes) (30%) –Final Exam (40%) Class participation will help your grade! 14

homework If you do not do the homework programs, you cannot pass the course. If home work is late, 1 point (25%) is deducted. After one week of lateness, home work will not be accepted. Style counts from the beginning of this class. Submit the program via to the e-tutor (more on this later) Back-up your files: For you own good you must save all programs on a disk and back them up on another disk. Computer crashes or lost programs are not valid excuses for not handing in an assignment. 15

A Word About Cheating For the purposes of this class, cheating is defined as: –Copying all or part of another student's homework, project or exam. –Allowing another student to copy all or part of your homework, project, or exam. –Discussing homework concepts is fine, but you must submit your own work. If you are caught cheating, you will receive an immediate FAILURE for the course. 16

Student Civility In an effort to make this class enjoyable for everybody… –Please be on time to class! –Please do not talk to your friends and neighbors in class! It disturbs everyone, and makes it hard to concentrate. If you have a question, just ask me! –Please turn your pagers and cell-phones off! –Please do not sit in the back row. 17

Getting Help Help is always available! Option 1: Come to my Office Hours –Tuesdays, 11:00 am – 1:00 pm and Wednesdays, 5:00 – 6:00 pm (I may change the time of my office hours) –Location: Room 419 Warren Weaver Hall –I get bored when nobody visits! –If you cannot make my office hours, I will be happy to make an appointment with you. Please try to give me advance warning when you need an appointment. Option 2: Write to the class mailing list. Please do not send homework code to the list. 18

19 syllabus Chap. 1, Introductionto Java Chap. 2, Primitive Data Types Chap. 3, Control Statements Chap. 4, Methods Chap. 5, Arrays Chap. 6, Objects and Classes Chap. 7, Strings Chap. 8, Class Inheritance and Interfaces Chap. 9, Section 9.6. The wrapper classes. Chap. 12, Applets

Object Orientated Programming Objects –Reusable software components that model items in the real world –Meaningful software units Date objects, time objects, paycheck objects, invoice objects, audio objects, video objects, file objects, record objects, etc. Any noun can be represented as an object –Very reusable –More understandable, better organized, and easier to maintain than procedural programming –Favor modularity  2000 Prentice Hall, Inc. All rights reserved. 20

History of Java A group of 13 Sun employees including James Gosling started the “Green Project” in 1991 with the intention of planning for the next wave in computing. They designed the *7 which was “ an interactive, handheld home- entertainment device controller with an animated touchscreen user interface” Gosling’s contribution to the project was an entirely new processor independent language call “Oak”. 21

22 History or Java (continued) To make a long story short, people at Sun decided to use this new language for the web. At the Sun World conference in May 1995, Marc Andreessen of Netscape announced an agreement to integrate Java into its browser – in a nutshell - webpages were no longer going to be static. Over the next few years, java became very popular for writing applets (small programs included on webpages) Today in addition to writing applets, Java is used for writing large applications as well as applications for mobile devices For more on the history of Java, check out:

23 Characteristics of Java F Java is simple F Java is object-oriented F Java is distributed F Java is interpreted F Java is robust F Java is secure F Java is architecture-neutral F Java is portable F Java’s performance F Java is multithreaded F Java is dynamic  2003 Prentice Hall, Inc. All rights reserved.

24 Basics of a Typical Java Environment Java programs normally undergo five phases –Edit Programmer writes program (and stores program on disk) –Compile Compiler creates bytecodes from program –Load Class loader stores bytecodes in memory –Verify Verifier ensures bytecodes do not violate security requirements –Execute Interpreter translates bytecodes into machine language  2003 Prentice Hall, Inc. All rights reserved.

25 Typical Java environment Primary Memory Disk Editor Compiler Class Loader Program is created in an editor and stored on disk in a file ending with.java. Compiler creates bytecodes and stores them on disk in a file ending with.class. Class loader reads.class files containing bytecodes from disk and puts those bytecodes in memory. Phase 1 Phase 2 Phase 3 Primary Memory Bytecode Verifier Bytecode verifier confirms that all bytecodes are valid and do not violate Java’s security restrictions. Phase 4 Primary Memory Interpreter Interpreter reads bytecodes and translates them into a language that the computer can understand, possibly storing data values as the program executes. Phase 5  2003 Prentice Hall, Inc. All rights reserved.