G51PR1G51PR1
Introduction to Programming I2000-2001
University of NottinghamUnit 1 : Introduction
Overview
Background– Teaching Staff– Course Details– Assessment
PR1 Summary Resources Programming
– Programming Languages– High Level Languages– Interpreters / Compilers
Introduction to Java– Java History– Java Properties– Types of Programs– JDK tools– The HelloWorld program
Using CourseMaster
Teaching Staff
Lecturer : Tsintsifas Athanasios (thanassis)– [email protected] Room:C73 (mon 10-12) (wed 9-10) (fr 10-12)
CourseMaster Administrator : Pavlos Symeonidis – [email protected] Room:C73 (tues 2-6) (thur 2-6)
Help Desk: Tarek Hegazy,– [email protected] Room : C75
Lab Assistants (terminal room - lab hours). CourseMaster help (via email), [email protected]
Course Details
20ish lectures plus lab sessions. One to three coursework exercises per week. You will be assigned to 1 of 4 lab sessions
– 2-4 & 4-6 Tuesday – 2-4 &, 4-6 Thursday
Prerequisites : None (but you must do CUA concurrently). Objectives : To learn to think algorithmically and to express in
sound implementations.
Assessment 100% coursework via the CourseMaster system (used to be
called Ceilidh, check www.cs.nott.ac.uk/~ceilidh).
Assessment
Starting on Friday 13th of October Exercises close 10 days after opening (every Monday 12:00) Usually you have three attempts to submit. The last attempt is always the final. Feedback after each submission gives you enough information to
infer the correct the solution. More on the process of using CourseMaster on Friday.
Summary of PR1
9-10 units of 1-2 lectures
G51PR1
1INTRODUCTION
ELEMENTARYPROGRAMMING
CONDITIONALS LOOPS METHODS
ARRAYS
CLASSES
I/OSTRINGS
23 4 5
6
7
8
GUI
910
Variables
Identifiers
Types
Ope
rato
rsLa
yout
Background
Programming
Java
Compiling
Running
If...else...
switc
h.. c
ase.
.
for
whi
le
do
...w
hile Syn
tax
nest
ing
nestin
g
Par
amet
ers R
ecursion
Syntax
Algorithms
objects
Files
Streams
Processing
overview
abstractionprotection
design
Resources
Sun file servers (jdk is installed in solaris) PCs (jdk is installed in all lab PCs) CourseMaster installed in all lab PCs PFE editor or Emacs-JDE JDK 1.3 Course Transparencies : http://www.cs.nott.ac.uk/~azt/pr1
ReadingRecommended: Java Gently by Judy Bishop (Addison-Wes). Java. How to Program by Deitel & Deitel (Prentice Hall). Developing Java Software by Winder & Roberts (Wiley). Java in a Nutshell by Flanagan (O’Reilly). Thinking in Java (Bruce Eckel) (available on the web)Other Sources of Information: CourseMaster : http://www.cs.nott.ac.uk/CourseMaster Sun Java Tutorial :
– http://java.sun.com/docs/books/tutorial/getStarted/index.html WWW – general : search in www.google.com! Intense Java Course : http://www.cs.nott.ac.uk/~azt/java.htm
Programming
"A program is a sequence of instructions. A recipe, a musical score, and a knitting pattern are all programs."
P Grogono, Programming in Pascal.
- The way to deal with an impossible task is to chop it down into a number of merely very difficult tasks, and break each one of them into a group of horribly hard tasks, and each one of them into tricky jobs, and each one of them...
(Terry Pratchet, Truckers)
Programming Languages
There are four basic programming language levels:– machine language– assembly language– high-level language– fourth-generation language
Each CPU has its own specific machine language The other levels were created to make programming easier
Programming Languages
A program must be translated into machine language before it can be executed on a particular type of CPU
This can be accomplished in several ways A compiler is a software tool which translates source code into a
specific target language Often, that target language is the machine language for a
particular CPU type The Java approach is somewhat different
High Level LanguagesOld-fashioned languages include:
BASIC - often used by beginners on home computers. FORTRAN - old but still popular with some scientists and engineers,
new versions are introduced every few years. Algol - an elegant little-used internationally designed language, whose
features are being incorporated into other languages. COBOL - a widely used and well standardised language used in
commerce. APL - an interactive scientific language with a very mathematical
notation. PL/I - a failed attempt by IBM at achieving an all-purpose language,
now almost dead.
High Level LanguagesOther Languages :
Pascal - good for beginners, often taught as a first language. Modula2 - a development of Pascal to make it more realistic for large
programs, and to enable modern program design techniques to be used.
C - a practical language, see below. C++ - an object-oriented development of C. ADA - a USA Department of Defense standard, now adopted by the
UK Ministry of Defense also, aimed at safe programming for real-time embedded systems.
Java – A robust, secure, portable, network enabled variation on C/C++.
High Level Languages
Compare the COBOL:rate_per_hour multiplied by hours_worked gives gross_pay with C/C++:pay = rate * hours
Some language aims:understanding, documentation –> commercial (eg COBOL). handling vectors or complex numbers –> scientific/engineering (FORTRAN). simplicity –> beginners (Basic, Pascal). safety –> real time systems (ADA, Modula-2). complexity –> object-oriented (C++, Eiffel, Java).
Interpreters vs Compilers
Interpretation : BASIC & APL are interpreted. Each line is decoded and interpreted by the computer as it is executed. Instructions in loops may have to be interpreted many times. This is inefficient and causes the computer to run slowly.Compilation : Most other languages are compiled. Whole program first analysed by a compiler (another program). Converted into a machine executable form. Runs much faster (an order of magnitude or more). Can apply many types of optimisation during or after compilation. In two parts – compilation into an object module, then loading/linking into the
executable.
Java: What is it?
Simple Object Oriented Distributed Interpreted Robust Secure
Sun’s Description….Java is a :
• Architecture Neutral• Portable• High Performance• Multithreaded and
Dynamic
programming language. It contains an extensive library of classes for graphics programming, input/output, string handling, maths functions, basic data structures, etc.
Java History C language was evolved as a portable operating system language Dennis Ritchie (at Bell labs) developed it from B (which came from
BCPL). Originally ran on a DEC PDP-11 computer in 1972. C++ is an object-oriented extension to C developed by Bjarne
Stroustroup early 80’s. Sun had an internal corporate research project, Green, in 1991, to
develop intelligent consumer devices. Project lead to the language Oak (James Gosling) based on C/C++. Oak about to be cancelled when WWW came along. Sun saw renamed Oak to Java and saw potential for use on the web Java formally announced in May ’95. Since then, Java generated huge interest.
Java’s Versions
Java was officially announced in May 1995
9991 92 93 94 95 96 97 98
First Idea
Green Project OAK
Java 1.02
Java 1.1Java 1.2
00
Java 1.3
Java 1.2.2
Simple
Has a small set of Language Constructs. Borrows the C and C++ syntax. Is free from pointers. Uses Garbage Collection. Does not use header files and preprocessors.
Object Oriented
Not hybrid like C++. Supports the basic notions of OO :
– Abstraction,– Modularity,– Encapsulation,– Hierarchy,– Typing,– Concurrency,– Persistance.
Distributed
Works on a variety of platforms. Provides support for :
• Networking,• Internet,• Remote Objects.
Interpreted
Java Compiler
Java Source
File
Java Bytecode
FileJava
Bytecode File
Java Bytecode
File
JVM
The Java compiler translates Java source code into a special representation called bytecode
Java bytecode is not the machine language for any traditional CPU Another software tool, called an interpreter, translates bytecode into
machine language and executes it Therefore the Java compiler is not tied to any particular machine Java is considered to be architecture-neutral
Robust
Exception and Error handling. Multi-Tasking. Memory protection and management. Allows Modular development. Extensive compile-time checking.
Secure The features of bytecode and its interpretation, prevent
unintentional or intentional sabotage of compiled programs. Security has been considered in many levels.
Architecture Neutral
Bytecode can run on any JVM on any platform. “Write Once run Anywhere”. JDK implementation on many platforms.
Java Bytecode
MacVM
Win95VM
SolarisVM
MacOS Win95 Solaris
JavaHW
Portable
The bytecode can run on virtual machines (VM) above different operating systems :
• MacOS • Windows95/NT/CE• Solaris • OS2 • etc
It can also run directly on hardware.
High - Performance
Multithreading allows more than one task in a program. With JIT compilers the interpreted code compiles at run time and
gives almost native code speed.
Java Bytecode
Native
Operating System
Hardware
JIT JavaVM Java
OSJavaHW
Dynamic
Java has been built to support the development of dynamically extendable systems.
Java provides dynamic linking of the binary code at runtime.
Java’s Genealogy
Java : Types of Programs
Applets :• Execute on HTML Browsers.• Have severe security restrictions.
GUI Applications :• Are Interpreted and Executed.• Use the current’s platform’s GUI widgets.• Mostly use Java’s AWT or JFC packages.
Console Applications :• Simple Text Console.
JDK basic tools
javac (Compiler) .java->.class• The Java Language Compiler that you use to compile
programs written in Java into bytecodes. Example : java HelloWorld.java
java (Interpreter) executes .class• The Interpreter that you use to run programs written in Java.
Example : javac HelloWorld javadoc (Doc. generator) .java html
• Generates documentation in HTML format from Java source code. Example : javadoc HelloWorld.java
public class HelloWorld {
public static void main(String argv[] ) { System.out.println("Hello World!!!"); }}
The First Java Program
Filename: HelloWorld.java
CourseMaster
CourseMaster is a “Courseware” system that provides for :– The presentation of Information
• summaries, notes, coursework questions, hints, daily messages– The administration of coursework
• coursework delivery, • submission management, • overall class management
– The automatic assessment of coursework • solution space modeling, • assessment and feedback mechanisms, • plagiarism checking tools
Logging in CM client:
To login to CM you need both a windows and a unix password. Once you are in windows you can click the “CM” icon This will get you to the login screen :
Unix Password!
Message of the day :
Informs you about the latest in exercises Do read it!
CourseMaster Course Level :
Options Exit
MOTD Notes Summary
CourseMaster Unit Level
Notes Summary
CourseMaster Exercise Level :
Setup Develop Submit Question View TD Marks Run Run TD
Setup :
Puts the skeleton source and other files in your working area
Do not setup over your solution
Develop :
PFE is CM’s standard editor for Java source
You can always change it later on!
Compile :
From Menu : Execute->javac
After Compilation :
Good News
Bad NewsCtrl + G Gets you to any line number
Run a program
Two options : 1. From PFE, Execute->java
– PFE : Options->Preferences->Execute Menu->java->Edit :– Start command (as independent process OR capture output)
2. From CourseMaster, Exercise Level->Run
Submit
After having developed the solution you need to refresh the CM browser by refreshing the course tree structure.
You will be asked to confirm and then wait for the result.
ExpandedResult tree
Submission NumberFeedback for every check
Other Options :
View TD : Allows you to see the testing input that CM uses for the particular exercise.
Marks : Allows you to check the exercise’s last submission
Options : Allows you to change : – Visual properties.– Editor command.
Summary
Background– Teaching Staff– Course Details– Assessment
PR1 Summary Resources Programming
– Programming Languages– High Level Languages– Interpreters / Compilers
Introduction to Java– Java History– Java Properties– Types of Programs– JDK tools– The HelloWorld program
Using CourseMaster