CPCS-202
LAB -1
Instructor Information
Uzma Hashmi
Office: B# 7/ R#1-121
E-mail address: uzma_a2001@yahoo.com
Group Email Addresses
Post message: cs202-lab@yahoogroups.com
Subscribe: cs202-lab-subscribe@yahoogroups.com
I will use this group to communicate and all the Slides will be posted on the
group after each lesson
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Learning Outcomes of Lab-1
1.
2.
3.
4.
5.
6.
7.
Installation of jdk1.7 and IDE ECLIPSE
Understanding the IDE
Writing ,Running and Debugging the code
Studying the structure of a Java Program
Adding Comments
White Spaces
Identifiers
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• In this semester we will learn JAVA
• The IDE (integrated development
environment)we will use will be Eclipse
• The compiler is jdk(java development kit)
• Now we will see how can we install both in
Part A and Part B
See next slides for the installation steps
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• First you need to install jdk for java language
compilation
• To do so we'll access this web link
http://www.oracle.com/technetwork/java/javase
/downloads/index.html
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Step 1:
http://www.oracle.com/technetwork/java/javase/downloads/
index.html
• JRE (Java Runtime Environment) on your
system to run Java applications and applets.
To develop Java applications and applets, you
need the JDK (Java Development Kit), which
includes the JRE
JRE (Java Runtime Environment) on your system to run Java
applications and applets. To develop Java applications and
applets, you need the JDK (Java Development Kit), which
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includes the JRE
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http://www.eclipse.org/downloads/
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Extract the files and there you get the
files listed below
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Using Eclipse
• The system will prompt you for a workspace.
The workspace is the place there you store
your Java projects (more on workspaces later).
Select a suitable (empty) directory and press
Ok.
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Click here
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Creating Java Project
Select from the menu File ->
New-> Java project.
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Creating Packages inside the work-space
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Another way of
Running your code
Debug Run
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Use of Refactor
Once you have created your file ,you can change
the name of the file using the refactor option
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Error description in Problems
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Structure of the program
• In the Java programming language:
– A program is made up of one or more classes
– A class contains one or more methods
– A method contains program statements
• These terms will be explored in detail throughout
the course
• A Java application always contains a method
called main,
• A Java application name must be the same as the
class name.
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Java Program Structure
//
comments about the class
public class MyProgram
{
class header must be the same
As the java program name
MyProgram.java
class body
Comments can be placed almost anywhere
}
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Java Program Structure
//
comments about the class
public class MyProgram
{
//
comments about the method
public static void main (String[] args)
{
method body
method header
}
}
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Program.java
//********************************************************************
// Program.java
Author: Lewis/Loftus
//
// Demonstrates the basic structure of a Java application.
//********************************************************************
public class Program
{
//----------------------------------------------------------------// Prints a presidential quote.
//----------------------------------------------------------------public static void main (String[] args)
{
System.out.println ( "A quote by Abraham Lincoln:” );
//System is a predefined class that provides access to the system.
//out is the output stream that is connected to the console{e.g. Monitor}.
//println() - Displays the String which is passed to it.
System.out.println ( "Whatever you are, be a good one.” );
}
}
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Comments
• Comments in a program are called inline documentation
• They should be included to explain the purpose of the
program and describe processing steps
• They do not affect how a program works
• Java comments can take three forms:
// this comment runs to the end of the line
/*
this comment runs to the terminating
symbol, even across line breaks
*/
/** this is a javadoc comment
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*/
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Identifiers
• Identifiers are the words a programmer uses in a program
• An identifier can be made up of letters, digits, the underscore character ( _ ),
and the dollar sign
• Identifiers cannot begin with a digit
• Java is case sensitive - Total, total, and TOTAL are different
identifiers
• By convention, programmers use different case styles for different types of
identifiers, such as
– title case for class names - Lincoln
– upper case for constants – MAXIMUM
– Combination(Compound Word)opt. -Camel Notation
– E.g Class Name :MyProject
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Identifiers cont.
• Often we use special identifiers called
reserved words that already have a predefined
meaning in the language ( such as void )
• A reserved word cannot be used in any other
way
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Reserved Words
• The Java reserved words:
abstract
assert
boolean
break
byte
case
catch
char
class
const
continue
default
do
double
else
enum
extends
false
final
finally
float
for
goto
if
implements
import
instanceof
int
interface
long
native
new
null
package
private
protected
public
return
short
static
strictfp
super
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switch
synchronized
this
throw
throws
transient
true
try
void
volatile
while
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White Space
• Spaces, blank lines, and tabs are called white
space
• White space is used to separate words and
symbols in a program
• Extra white space is ignored
• A valid Java program can be formatted many
ways
• Programs should be formatted to enhance
readability, using consistent indentation
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//**************************************************
// Poem.java
//
// Prints a classic poem on four lines.
//**************************************************
public class Poem
{
public static void main(String[] args)
{
System.out.println("Roses are red");
System.out.println("Violets are blue");
System.out.println("Sugar is sweet");
System.out.println("And so are you!");
}
}
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Example for white spaces
//********************************************************************
// Lincoln3.java
Author: Lewis/Loftus
// Demonstrates another valid program that is poorly formatted.
//********************************************************************
public
class
Lincoln3
{
public
static
void
main
(
String
[]
args
)
{
System.out.println
(
"A quote by Abraham Lincoln:"
)
;
System.out.println
(
"Whatever you are, be a good one."
)
;
}
}
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Lab Assignment
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