BIT- Revision

Java Robot (‘’,)

2010-04-23T22:41:00.001-07:00

සුභ අලුත් අවුරුද්දක් හැමෝටම ! ! !

ඉතින් ඔන්න මම මේ අලුත් අවුරුද්දෙ පොඩ්ඩක් Java Programming වලට ආස හිතෙන විදියෙ ලිපියක් ලියන්න ඕනෙ කියල හිතුවා.

ඔක්කෝටම කලින් ඔයාල හැමෝගෙන්ම පුන්චිම පුන්චි ඉල්ලීමක් කරන්න ඕනෙ, ඒ තමයි මේකට use කරල තියෙන code කාටවත් කරදරයක් කරන්න නම් පාවිච්චි කරන්න නම් එපා කියන එක.

ඔයාලට මතක ඇති අපි මුල්ම පියවර විදියට java වලින් software එකක අතුරු මුහුනතක් එහෙමත් නැත්තන් interface එකක් හදා ගත්තා.(My First Java Program)ඉතින් අපි මේ පාරත් ඒ විදියටම අලුත්ම program එකක් හදාගන්න විදිය පොඩ්ඩක් ඉගෙන ගමු. මේ සැරේ අපි කරන්න යන්නෙ ටිකක් විතර FUN වැඩක් කියලයි මට හිතෙන්නෙ.(ඔයාලට එහෙම හිතෙන එකක් නැද්ද දන්නෙ නෑ හැබැයි.) ඉතින් කෝකටත් කියල අගේ කරන එක පැත්තකින් තියල වැඩේ කියල ඉන්නම්කෝ.ඔන්න ඔයාල හොදයි කියල හිතෙනව නම් විතරක් කරල බලන්නකෝ....

මේ වැඩේ කරන්න මම use කරල තියෙන ප්‍රධාන class එක නම් හැබැයි අපේ syllabus එකට නැහැ. ඒත් මම හිතුවා මේකෙ තියෙන for loop ටික තේරුම් ගන්න එක ඔයාලට හතරවෙනි පාඩමේ Iterative Statement කරද්දි පුන්චි හරි උදවුවක් වෙයි කියල.

ඉතින් program එක සරලයි.

1). මුලින්ම අලුත් Notepad එකක් open කරගෙන පහල තියෙන code එක type කරගන්න.

import java.awt.Robot;

import java.awt.event.*;

//@author bit-revision.blogspot.com

public class MyRobot {

public static void main(String[] args) {

try {

Robot r = new Robot();

r.keyPress(KeyEvent.VK_WINDOWS); r.keyRelease(KeyEvent.VK_WINDOWS); Thread.sleep(200);

r.keyPress(KeyEvent.VK_P); r.keyRelease(KeyEvent.VK_P); Thread.sleep(200);

r.keyPress(KeyEvent.VK_RIGHT); r.keyRelease(KeyEvent.VK_RIGHT); Thread.sleep(200);

r.keyPress(KeyEvent.VK_A); r.keyRelease(KeyEvent.VK_A); Thread.sleep(200);

r.keyPress(KeyEvent.VK_RIGHT); r.keyRelease(KeyEvent.VK_RIGHT); Thread.sleep(200);

r.keyPress(KeyEvent.VK_P); r.keyRelease(KeyEvent.VK_P); Thread.sleep(200);

r.keyPress(KeyEvent.VK_ENTER); r.keyRelease(KeyEvent.VK_ENTER); Thread.sleep(200);

r.keyPress(KeyEvent.VK_ALT); r.keyPress(KeyEvent.VK_TAB); Thread.sleep(200);

r.keyRelease(KeyEvent.VK_ALT); r.keyRelease(KeyEvent.VK_TAB); Thread.sleep(200);

r.mouseMove(100, 100); Thread.sleep(500);

r.mousePress(MouseEvent.BUTTON1_MASK); r.mouseRelease(MouseEvent.BUTTON1_MASK);

for(int i=0;i<100;i++){

r.mousePress(MouseEvent.BUTTON1_MASK); r.mouseMove(100+i, 100); Thread.sleep(20);

}

r.mouseMove(150, 100);

for(int i=0;i<100;i++){

r.mousePress(MouseEvent.BUTTON1_MASK); r.mouseMove(150, 100+i); Thread.sleep(20);

}

for(int i=0;i<25;i++){

r.mousePress(MouseEvent.BUTTON1_MASK); r.mouseMove(150-i, 200+i); Thread.sleep(20);

}

for(int i=0;i<25;i++){

r.mousePress(MouseEvent.BUTTON1_MASK); r.mouseMove(125-i, 225-i); Thread.sleep(20);

}

r.mouseRelease(MouseEvent.BUTTON1_MASK);

} catch (Exception ex) { }

}

2). ඊට පස්සෙ ඒ Ctrl+S press කරල C: drive එකේ save
කරගන්න.(MyRobot.java)

3). ඉන් පසුව start > run වෙත ගොස් CMD ලෙස type කර enter කිරීමෙන් Command Prompt එකක් ලබා ගන්න.

4). ඉන් පසු Path එක Set කර ගෙන ඇත්නම් Compile කිරීම සදහා C: වෙත ගොස් javac MyRobot.java ලෙස type කර enter කරන්න.

Path එක Set කරගෙන නැත්නම් එය කර ගැනීමට Set Java Path යන්න උදව් කරගන්න.

5). ඉන් පසු Error කිසිවක් මතු නොවූයේ නම් Run කරවීම සදහා java MyRobot ලෙස type කර enter කරන්න.

6). ඔබට දැන් ඔබගේ අනුදැනුමකින් තොරව Paint හි රූප අදිනු දැකගත හැකි වනු ඇත.

Run කර බැලීමට අවශ්‍ය නම් මෙතනින් Download කරගෙන Double Click කරන්න.

My First Java Program

2010-04-02T04:33:00.000-07:00

bit-revision.blogspot.com

fudkjo fï JAVA lshkafka@
Thdg uu lsjqfjd;a JAVA lshkafka mß.Kl jevigyka (Computer Programs) iïmdokhg Ndú;d lrk mß.Kl NdIdjla (Computer Language) lsh,d Thdg f;areï .kak mq¿jkao@ iuyr úg flfkl=g tal fkdf;afrkak;a mq¨jka' ir,j lshkjkï wms wfma woyia yqjudre lr .ekSug;a" hï ld¾hhla lrjd .ekSsug ksfhda. ksl=;a lsßug;a isxy," bx.%sis fyda fjkhï NdIdjla Ndú;d lrkjd fkao@ tfiau mß.Klh yd woyia yqjudre lr .ekSug;a" mß.Klh ,jd hï ld¾hhla bgq lr .ekSug;a C, JAVA fyda fjkhï mß.Kl NdIdjla Ndú; l, yelsh' tfia kï flfkl=f.ka fukau mß.Klhlskao hï ld¾hhla lrjd .ekSsug kï mß.Klhg f;areï .; yels NdIdjla m%.=K lsÍu l, hq;=u jk nj Tng f;areï .; yelshs fkao@ u;la lr n,kak Thd fkdokak NdIdjlska lshmq fohla f;areï .kak nerej m%;spdr olajkak nerej .sh wjia:djla .ek ' ' ' ±ka Thdg mß.Kl NdIdjla .ek f;areï .kak mq¨jka we;s' ta;a fï mß.Kl jevigyka tfyu;a ke;akï uDÿldx. lshkafka fudkjdo@ Thd lsisu mß.Kl NdIdjla ±kf.k fkdysáhd lshd is;uq' ta;a Thdg mß.Klh Ndú; lrf.k
bka ,smshla msgm;a lr.ekSu jeks hula lr.ekSug l%uhla ;sfhkjd fkao@ ta ;uhs mß.Kl NdIdjla W.;a mß.Kl bxðfkarejl= úiska bx.%Sis NdIdjg mßj¾;kh lrk ,o w;rueÈ w;=re uqyqK;la jk uDÿldx.hla Ndú;d lsÍu' th yßhg NdId mßj¾;lfhl=f.a ld¾hhg iudkhs' b;ska Tng jegfykjdo Tn fuf;la mß.Klfha w;rueÈhka
iuÕ jev lghq;= isÿ lr we;s nj'

tfia kï wms wfma uDÿldx.h idod .ekSu wdrïN lruq' m<uqj Start > All Programs > Accessories > Notepad fj; f.dia kj Notepad window tlla open lr.kak' tys my; ±lafjk fla; fyj;a code fma,s space, symbols and case (Capital letter & Simple letter) .ek wjOdkh fhduq lrñka type lr .ekSu lrkak'(code
i) ^1 jk rEmh&

import javax.swing.JFrame ;

class Y extends JFrame {

public static void main (String args[]) {

JFrame myFrame = new JFrame ("By SHYN");

myFrame.setSize (300, 400) ;

myFrame.setVisible (true) ;

}

bkamiq Notepad ys jï fl,jf¾ by,ska we;s File > Save As fj; hkak' újD; jk kj Save As window ys Save in: f,i i|yka ;ek bÈßfha we;s Drop Down fukqfjka (Combo Box tflka& Local Disk (C:) hkak Select lrkak.(fuys§ Local Disk (C:) hkak Tn rename lr we;akï ta ms<sn| fkdi,ld (C:) f,i i|yka jk Hard Disk Partition tl f;dard .kak& miqj my<ska we;s File name: bÈßmsg we;s Drop Down fukqfõ Y.java f,i type lrkak'miqj Save button tl click lr save lr .kak' ^2 jk rEmh&

Tn ±ka m<uq mshjr jk Java Program tlg wod, fla; igyka we;=,;a file tl Tnf.a oDv ;eáfha (Hard Disk) save lrf.k wjika' ±ka tu jevigyk run lsÍu i|yd l, yels l%u lSmh w;=ßka Tng myiq hehs yefÕk .bat File tlla (BATCH File) idod .ekSssfuka run lrjk whqre n,uq'

fï i|yd kej; fmr mßÈu Start > All Programs > Accessories > Notepad yryd kj Notepad window tlla open lr.kak' tys run lrùug wjYH jk my; commands fma,s type lr .kak'(code
ii) ^3 jk rEmh&

C :

CD \

Path = C:\Program Files\java\jdk1.6.0_10\bin

javac Y.java

java Y

pause

bka miq tyso File > Save As fj; f.dia fmr isÿl, whqßkau Save in: bÈßfha we;s Drop Down tflka Local Disk (C:) f;darkak' bkamiq File name: hgf;a we;s Drop Down tfla Y.bat f,i type lr Save button tl click lrkak' ^4 jk rEmh&

±ka Tn Tnf.a My Computer > Local Disk (C:) fj; f.dia tys we;s files w;r Tn save lr.;a Y.java iy Y.bat f,i i|yka file 2 la we;a ±hs n,kak' tfia kï Tn ±ka Tnf.a m,uq uDÿldx.h ksujd wjika' kuq;a Tn Tfí uDÿldx.h run lrùug yels jk mßÈ Tfí mß.Klh ;=< JAVA ia:dmkh (Install) lrf.k fkdue;s ksid ;ju Tnf.a uDÿldx.h run lsÍu l, fkdyel' Tn uDÿldx. bxðfkarejrefjl= ùfï§ l=uk mß.Kl NdIdjla mdúÉÑ l,o ta i|yd tu NdIdjg wod,j mß.Klh ilid .ekSu wksjd¾h jk w;r JAVA j,§ fï ;;a;ajh tfiau jqjo th lsÍu w;sYhskau myiq lghq;a;ls'

fï i|yd Tng we;af;a JAVA Development Kit fyj;a JDK kñka y÷kajk uDÿldx.h Tfí mß.Klfha ia:dmkh (Install) lr.ekSu muKls' ta i|yd Tn JDK Setup file tlla fidhd .; hq;= fõ' wm fuysÈ th imhd .; yels wdldr bÈßm;a lrk w;r bka tla l%uhlska Setup file tl fidhd .ekSu Tnf.a JAVA f,dalhg msúiSug l, yels wju yd tlu wdfhdackh jk nj fu;kÈ i|yka l, hq;=uh'

JDK tl imhd .; yels wdldr

wka;¾cd,h (Internet) yryd

http://www.java.com/en/download/index.jsp

Èjhsk mqrd msysgd we;s ´kEu uDÿldx. wf,úie,lska b;du iq¨ uqo,lg JAVA j,g wod, ish¨u tools iuÕ ,nd .; yel'

by; hï wdlrhlska JDK Setup file tl Tn fidhd .;af;a kï" th Double click lrkak' bkamiq tk window ys Accept button tl click lrkak' fojk window ys Next button tl click l, miq setup ùu isÿjk w;r wjika window ys Finish button tl click lrkak' ^5 jk rEmh& túg ReadMe.html file tl újD; jk w;r th lshùu ;=<ska JDK ms<sn|j jeäÿr f;dr;=re ±k .; yels fõ'

fuys§ Tn install lr.kakd JDK version tl ms<sn|j (code
ii) ys§ ie,ls,su;a úh hq;= jk w;r JDK version tl ±k .ekSug C:\Program Files\Java hk folder tl fj; f.dia tys iE§ we;s foders w;r jdk1.6... f,i mgka .kakd folder tflys ku n,d .; hq;= fõ' Wod( tu folder tflyss ku jdk1.6.0_14 kï Tn by; i|yka (code
ii) ys 3 jk fma,sh C:\Program Files\Java\1.6.0_14\bin f,i fjkia lr File > Save fj; f.dia l, fjkig wod,j save lr .ekSu l< hq;= fõ' tfia kï Tn ±ka Tnf.a uDÿldx.h run lrùug iQodkï' ±ka Tn My Computer > Local Disk (C:) fj; f.dia tys we;s Y.bat hk file tl u; double click lrkak' Tn Tnf.a codes ksjerÈj type lr save lr .;af;a kï Tng DOS ;srhla Èia ù ta iuÕu Tfí m,uq uDÿldx.fha uqyqK; Tngu Èia fõú' ^6 jk rEmh& n,kak tys title tlys "By SHYN" f,i i|yka jkjd fkao@ ±ka Tn Y.java file tl Notepad yryd open lrf.k "By SHYN" f,i i|yka ia:dkhg Tnf.a kula fhdod save lr kej; run lr n,kak' Tfíu ku software tll olskak yelshdjla Tng ±ka ;sfnkjd' tfia kï Tn JAVA f,dalhg uq,a mshjr ;nd wjika'

iïmdokh : kÿka ,shkf.a

PDF FORMAT -

Can't Read this. Download FONT

Second Lesson in JAVA

2010-04-02T04:05:00.001-07:00

Theory Session

How Java Works On Computer

When programming you will be writing source code using the syntax for the java programming language. This source code is translated into byte code by the compiler and is then stored in a .class file. The byte code is the same for each computer system.

For this byte code to execute, another program, called the Java virtual machine (JVM), translates the Java byte code into instructions understood by that computer. This extra step is necessary for one of the main advantages of Java: the same program can run in any computing environment! A computer might be running Windows, MacOS, Solaris, Unix, or Linux-each computer system has its own Java virtual machine program. Having a particular Java virtual machine for each computer system also allows the same Java .class file to be transported around the internet. The following figure shows the levels of translation needed in order to get executable programs to run on most computers.

Elements of Java Programming

The essential building block of Java programs is the class. In essence, a Java class is a sequence of characters (text) stored as a file, whose name always ends with .java. Each class is comprised of several elements, such a class heading (public

class class-name) and methods—a collection of statements grouped together to provide a service. Below is the general form for a Java class that has one method: main. Any class with a main method, including those with only a main method, can be run as a program.

A simple Java program (only one class)

import package-name.class-name;

public class class-name {

public static void main(String[ ] args) {

variable declarations and initializations

messages and operations such as assignments

}

}

General forms describe the syntax necessary to write code that compiles. The general forms in this textbook use the following conventions:

Boldface elements must be written exactly as shown. This includes words such as public static void main and symbols such as [, ], (, and ).

Italicized items are defined somewhere else or must be supplied by the programmer.

An Example of a Syntactically Correct Java Class with One Method Named main

// Read a number and display that input value squared

import java.util.Scanner;

public class ReadItAndSquareIt { // Class heading
public static void main(String[] args) { // Method heading
// Declare three variables
int number; // Variable declaration
int result = 0; // Variable initialization
Scanner keyboard = new Scanner(System.in); // Class instantiation
// Prompt user for a number and get it from the keyboard
System.out.print("Enter an integer: "); // Message
number = keyboard.nextInt(); // Message and assignment
result = number * number; // Assignment
System.out.println(number + " squared = " + result);
}

}

Out Put
Enter an integer: -12
-12 squared = 144

The first line in the program shown above is a comment indicating what the program will do.

Comments in Java are always preceded by the // symbol, and are "ignored" by the program. The next line contains the word import, which allows a program to use classes stored in other files. This program above has access to a class named Scanner for reading user input. If you omit the import statement, you will get this error:

Scanner keyboard = new Scanner(System.in);

Scanner cannot be resolved to a type

Java classes are organized into over seventy packages. Each package contains a set of related classes. For example, java.net has classes related to networking, and java.io has a

collection of classes for performing input and output. To use these classes, you could either use

the import statement or simply precede the class name with the correct package name, like this:

java.util.Scanner keyboard = new java.util.Scanner(System.in);

The next line in the sample program is a class heading. A class is a collection of methods and

variables (both discussed later) enclosed within a set of matching curly braces. You may use any valid class name after public class; however, the class name must match the file name.

Therefore, the preceding program must be stored in a file named ReadItAndSquareIt.java.

The file-naming convention

class-name.java

The next line in the program is a method heading that, for now, is best retyped exactly as shown:

public static void main(String[] args) // Method heading

The opening curly brace begins the body of the main method, which is a collection of executable statements and variables. This main method body above contains a variable declaration, variable initializations, and four messages, all of which are described later in this chapter. When run as a program, the first statement in main will be the first statement executed. The boy of the method ends with a closing curly brace. This Java source code represents input to the Java compiler. A compiler is a program that translates source code into a language that is closer to what the computer hardware understands. Along the way, the compiler generates error messages if it detects a violation of any Java syntax rules in your source code. Unless you are perfect, you will see the compiler generate errors as the program scans your source code.

Tokens — The Smallest Pieces of a Program

As the Java compiler reads the source code, it identifies individual tokens, which are the smallest recognizable components of a program. Tokens fall into four categories:

Token	Examples
Special symbols	; () , . { }
Identifiers	main args credits courseGrade String List
Reserved identifiers	public static void class double int
Literals (constant values)	"Hello World!" 0 -2.1 'C' true

Tokens make up more complex pieces of a program. Knowing the types of tokens in Java should help you to:

More easily write syntactically correct code.
Better understand how to fix syntax errors detected by the compiler.
Understand general forms.
Compete programs more quickly and easily.

Special Symbols

A special symbol is a sequence of one or two characters, with one or possibly many specific

meanings. Some special symbols separate other tokens, for example: {, ;, and ,. Other special

symbols represent operators in expressions, such as: +, -, and /. Here is a partial list of singlecharacter

and double-character special symbols frequently seen in Java programs:

() . + - / * =< >= // { } == ;

Identifiers

Java identifiers are words that represent a variety of things. String, for example is the name of a class for storing a string of characters. Here are some other identifiers that Java has already given meaning to:

sqrt String get println readLine System equals Double

Programmers must often create their own identifiers. For example, test1, finalExam, main,

and courseGrade are identifiers defined by programmers. All identifiers must follow these

rules:

Identifiers begin with upper- or lowercase letters a through z (or A through Z), the dollar sign $, or the underscore character _.
The first character may be followed by a number of upper- and lowercase letters, digits (0 through 9), dollar signs, and underscore characters.
Identifiers are case sensitive; Ident, ident, and iDENT are three different identifiers.

Valid Identifiers

main Vector incomeTax MAX_SIZE $Money$

Maine URL employeeName all_4_one _balance

miSpel String A1 world_in_motion balance

Invalid Identifiers

1A // Begins with a digit

miles/Hour // The / is not allowed

first Name // The blank space not allowed

pre-shrunk // The operator - means subtraction

double // This is reserved

Java is case sensitive. For example, to run a class as a program, you must have the identifier

main. MAIN or Main won't do. The convention employed by Java programmers is to use the

"camelBack" style for variables. The first letter is always lowercase, and each subsequent new

word begins with an uppercase letter. For example, you will see letterGrade rather than

lettergrade, LetterGrade, or letter_grade. Class names use the same convention, except

the first letter is also in uppercase. You will see String rather than string.

Reserved Identifiers

Reserved identifiers in Java are identifiers that have been set aside for a specific purpose. Their

meanings are fixed by the standard language definition, such as double and int. They follow the

same rules as regular identifiers, but they cannot be used for any other purpose. Here is a partial list

of Java reserved identifiers, which are also known as keywords.

Java Keywords

boolean default for new

break do if private

case double import public

catch else instanceOf return

char extends int void

class float long while

The case sensitivity of Java applies to keywords. For example, there is a difference between

double (a keyword) and Double (an identifier, not a keyword). All Java keywords are written in

lowercase letters.

Literals

A literal value such as 123 or -94.02 is one that cannot be changed. Java recognizes these

numeric literals and several others, including String literals that have zero or more characters

enclosed within a pair of double quotation marks.

"Double quotes are used to delimit String literals."

"Hello, World!"

Integer literals are written as numbers without decimal points. Floating-point literals are written

as numbers with decimal points (or in exponential notation: 5e3 = 5 * 103 = 5000.0 and 1.23e-4

= 1.23 x 10-4 = 0.0001234). Here are a few examples of integer, floating-point, string, and char5

acter literals in Java, along with both Boolean literals (true and false) and the null literal value.

The Six Types of Java Literals

Integer	Floating Point	String	Character	Boolean	Null
-2147483648	-1.0	"A"	'a'	true	null
-1	0.0	"Hello World"	'0'	false
0	39.95	"\n new line"	'?'
1	1.234e02	"1.23"	' '
2147483647	-1e6	"The answer is: "	'7'

Note: Other literals are possible such as 12345678901L for integers > 2,147,483,647.

Comments

Comments are portions of text that annotate a program, and fulfill any or all of the following

expectations:

Provide internal documentation to help one programmer read and understand another's program.
Explain the purpose of a method.
Describe what a method expects of the input arguments (n must be > 0, for example).
Describe a wide variety of program elements.

Comments may be added anywhere within a program. They may begin with the two-character

special symbol /* when closed with the corresponding symbol */.

/*

A comment may
extend over
many lines
*/

An alternate form for comments is to use // before a line of text. Such a comment may appear

at the beginning of a line, in which case the entire line is "ignored" by the program, or at the

end of a line, in which case all code prior to the special symbol will be executed.

// This complete Java program runs, but does nothing

public class DoNothing {
public static void main(String[] args) { // A method heading
// This program does nothing
}
}

Comments can help clarify and document the purpose of code. Using intention-revealing

identifiers and writing code that is easy to understand, however, can also do this.

Java has a third style of comments, known as javadoc comments. These begin with /** (note

the second asterisk) and end with */ , and contain documentation and special tags that show up in Web pages (when you run the javadoc program).

/** Debit this account by withdrawalAmount if it is no greater than this

* account's current balance. withdrawalAmount must be greater than 0.

* @param withdrawalAmount The requested amount of money to withdraw.

* @return true if 0 < withdrawalAmount <= the balance.

*/

public boolean withdraw(double withdrawalAmount)

Primitive Types

Java has two types of variables: primitive types and reference types. Reference variables store

information necessary to locate complex values such as strings and arrays. On the other hand,

Primitive variables store a single value in a fixed amount of computer memory. The eight

"primitive" (simple) types are closely related to computer hardware. For example, an int value

is stored in 32 bits (4 bytes) of memory. Those 32 bits represent a simple positive or negative

integer value. Here is summary of all data types in Java along with the range of value for the

primitive types:

Java's Data Types

Primitive Types Reference Types

integers: arrays (Later)

Name	Width	Range
byte	(8 bits)	-128 .. 127
short	(16 bits)	-32,768 .. 32,767
int	(32 bits)	-2,147,483,648 .. 2,147,483,647
long	(64 bits)	-9,223,372,036,854,775,808 .. 9,223,372,036,854,775,807

real numbers: classes (Later)

Name	Width	Range
float	(32 bits)	1.40129846432481707e-45 .. ±3.40282346638528860e+38
double	(64 bits)	±4.94065645841246544e-324 .. ±1.79769313486231570e+308

others: interfaces (Later)

Name	Width	Range
char	(16 bits)	0-65536
boolean		false .. true

Declaring a primitive variable provides the program with a named data value that can change

while the program is running. An initialization allows the programmer to set the original value of

a variable. This value can be accessed or changed later in the program by using the variable

name.

General Form: Initializing (declaring a primitive variable and giving it a value you want)

type identifier; // Declare one variable

type identifier = initial-value; // For primitive types like int and double

Example: The following code declares one int and two double primitive variables while it

initializes grade.

int credits;
double grade = 4.0;
double GPA;

The following table summarizes the initial value of these variables:

Variable Name Value

credits ? // Unknown

grade 4.0 // This was initialized above

GPA ? // Unknown

If you do not initialize a variable, it cannot be used unless it is changed with an assignment

statement. The Java compiler would report this as an error.

Assignment

An assignment gives a value to a variable. The value of the expression to the right of the

assignment operator (=) replaces the value in the variable to the left of the assignment operator

(=).

General Form: Assignment

variable-name = expression;

The expression must be a value that can be stored by the type of variable to the left of the

assignment operator (=). For example, an expression that results in a floating-point value can be

stored in a double variable, and likewise an integer value can be stored in an int variable.

credits = 4;

grade = 3.0;

GPA = 0.0;

After the two assignments execute, the value of both variables is modified and the values can be shown like this:

Variable Value

credits 4
grade 3.0
GPA 0.0

In an assignment, the Java compiler will check to make sure you are assigning the correct type of value

to the variable. For example, a string literal cannot be assigned to a numeric variable. A

floating-point number cannot be stored in an int.

grade = "Noooooo, you can't do that"; // ERROR: Can't store string in a double

credits = 16.5; // ERROR: Cannot store a floating-point number in an int

Practical Session

Create a class that class name should be your name. Save it in a different path (not in C:\). Compile it and Run it.
Identify given code sample's basic elements that categorized to below five categories.

Import statements
Classes
Methods
Variables
Comments

Create your own class and it must include below elements.

Import statement
Class
Method
Variable
Comment

Declare 8 variables in Primitive Data Types and save it as class "PDT".
Try these variable declarations and check them in right syntax or not.(Save it as "Integers.java")

Give them to a definition in given space.

In assume and real mark √ or ×.

Declaration	Assume	Real	Definition
byte b1=0;
Byte b2=0;
byte b3=128;
byte b4=-128;
byte b5=128;
byte b6=132;
short s1=4;
Short s2=1245;
int i1=128;
int i2=12.0;
int i3=-327682;
int i4=00;
int i5=38;
int i6=046;
int i7=0x26;
Int i8=5000;
long l1=0;
long l2=-0;
Long l3=5;
long l4=32769;

Try these variable declarations and check them in right syntax or not.(Save it as "Floatings.java")

Give them to a definition in given space.

In assume and real mark √ or ×.

Declaration	Assume	Real	Definition
float f1=0.0;
float f2=0.0f;
float f3=12F;
Float f4=-128.04F;
float f5=128F;
double d1=132.0;
double d2=4.5d;
double d3=1245.123D;
double d4=128;
double d5=12.;
double d6=0.003323;
double d7=6.022e23;
double d8=3.14E-05;
Double d9=23;

Try these variable declarations and check them in right syntax or not.(Save it as "Booleans.java")

Give them to a definition in given space.

In assume and real mark √ or ×.

Declaration	Assume	Real	Definition
boolean b1=true;
boolean b2=false;
Boolean b3=true;
boolean b4=True;
boolean b5=tRue;
boolean b6="true";
boolean b7=0;
boolean b8=null;
boolean b9=0<5;

IS - (02). IT Concepts

2010-02-17T14:21:00.000-08:00

1.1 - Overview of components

► Input ? - Convert data into electronic form (directly of or networks through)

Key board , Mouse

► Processing ? - Ability to process data & storage in primary storages.

CPU , Mother Board , RAM

► Out put ? - Convert electronic informations into human understandable formats.

Monitors , Printers

► Storages ? - Store data to use.

Primary storages ? - Volatile.

Secondary Storage

Hard Disk , Flash Drives

1.2 - CPU ? - Central Processing Unit.

► Arithmetic / Logic Unit (ALU) ? - Performs arithmetical and logical operations.

Arithmetic ? - + , - , / , *
Logical ? - > , < , =

► Control Unit ? - Control the flow of informations & instructions to run programs.data control between ALU and main memory.

► Registers ? - Store very small amounts of data & instructions for short time of period.

Machine cycle time ? - execution of an instruction take place during machine cycle , how many instructions are executed in a second. (MIPS)
Clock speed ? - Predetermined rate of a CPU to produce a series of electronic pulses. (MHz , GHz)
World length ? -No of bits the CPU can process at a one time.
Bus line width ? - No of bits a bus line (way of transfer data from CPU to other components) can transfer at a one time.

1.3 - Main Memory ? -(RAM , ROM , & Cache) Located close to CPU , Not inside the CPU , Series of chip sets which can store data in binary stream.

   ► RAM ? - Random Access Memory. It made of several storage locations which are Integrated Circuits , Them called as cells , Each cell has unique number called address , Randomly access , Volatile , Temporary stored.

   ► ROM ? - Read Only Memory , Data and instructions are stored in ROM permanently , Non volatile , Only can read , can not erase or modify. (Manufacture Data)

   ► Cache ? - CPU is much fast but not RAM. So cache memory chip is a bridge to transfer data between CPU and RAM to overcome of reducing of computer speed.

1.4 - Secondary storage? - Need of permanent data storage overcome by these , Non volatile.

   ► Access methods

Sequential access ? - Data must be accessed by pass the order of which it is stored. (Slow)
Direct access ? - Data can accessed directly by passing a sequential order. (Fast)

   Magnetic tapes ? - Sequential access.
   Magnetic disks ? - Direct access.
   Disks

   Hard disks ? - Use stacks of rigid magnetic disks with sealed cover , having read / write headers to transfer data.

   Floppy disks ? - Magnetic disk with a case , Wants a drive to transfer data , Portable , Low capacity , Slow than hard disks.

   Optical disks ? - Removable disks which data read and write from using a laser beam , Usually 12cm , High durability , Low cost.

   CD-ROM ? - Compact Disk Read Only Memory.
     WORM ? - Write Once Read Meny.
     RW-CD ? - Re-Writable CD

1.5 - Input Devices ? - Input devices allow user to enter data to the computer.

   ► Key board ? -Primary input device , Convert letters numbers and symbols into electrical signals.

   ► Pointing devices ? - Allow user to sense about a position in display of the monitor to computer.

     Mouse
     Track ball
     Joy stick

   ► Voice / Speech recognition system ? - This allows user to enter voice or sounds as data to the computer.

     Microphones

   ► Digital cameras ? - This allows to users enter image or video as data to the computer.

   ► Terminals ? - These are called as POS (Point Of Sales) devices , Use for data entering to the computer in another place , connect to computer using cables.

   ► Magnetic Ink Character Recognition (MICR) devices ? - Allow to read printed sheets letters.

   ► Light pens ? - Easy way to do drawings , hand writings and inject to computer.

   ► Touch sensitive screens ? - Allow touch sense in to the computer more easily.

   ► Scanning devices ? - Allow convert texts , drawings , photographs as data to the computer.

     Graphic Scanners
     Finger print scanners
     Bar code scanners

1.6 - Out put devices ? -Allow users to get back informations from the computers.

   ► VDU ? - Visual Display Units.

Monitor ? - These are create a graphical interface to users for view informations.

CGA ? - Color Graphic Adapter.
SVGA ? - Super Video Graphic Adapter

Monitors Categorized as ,

Monochrome / Color

CRT(Cathode Ray Tube) / LCD(Liquid Cristal Display)

► Printers & Plotters

Printers ? - Put on paper what on your monitor.
Plotters ? - High quality printouts on large papers , Able to move horizontally to draw complex continuous diagrams and graphics.

   ► Computer Output Microfilm devices ? - Place data from computer directly on to microfilm for future use.

   ► Music devices ? - Speakers head phones and other sound generate devices.

2.2 - Types of CS

Hand held computers
Portable computers
Thin client computers
Desktop computers
Work station computers
Server computers
Mainframe computers
Super computers

2.3 - Software ? - Set of programs designed to coordinate the activities & functions of the hardware and various programs through out the computer system.

► Types of Application Software ? - Application software gives organizations the ability to solve problems & perform specific activities and tasks.

Proprietary ? - Solve unique or specific problem.

Adv. - Meets user requirements , Provide flexibility in making modifications , Offers more control over the results.
Dis Adv. - Can take a long time & cost to develop , More risk to features & Performance .

Off-The-Shelf ? - Application softwares that already developed and available in market with providing standard functions.Generally gets by ASPs (Application Service Provider).

   Adv. - Low initial cost , Low risk for failure , High quality , Without bugs , Well tested.
   Dis Adv. - May pay for never use features , May lack important features , May not match current work process.

   ► Application Software Based on Usage

Personal Application Software

Word Processing ? - Transformed process of writing

MS Word , Lotus WordPro , Corel Word Perfect

Spread Sheet Analysis ? - Useful for business analysis , planning , modelling numbers and calculations & relationships(formulas)

MS Excel , Lotus 1-2-3

Database applications ? - Store manipulating and retrieve data.

MS Access , DBASE

Graphic program ? - Develop presentations , illustrations , and drawings.

MS PowerPoint , Lotus FreeLance , Corel Presentation

Personal information managers ? - Help to manage day-today works , appointments , notes , reminds , contacts & other informations. Sending email facility.

MS Out Look , Lotus Organizer

Online information services ? - Allow connect a personal computer to the outside world.
Software suits & integrated software packages ? - Collection of single application programs packed in a bundle. Work similarly.

Adv. - Easy to learn & use , icons and other resources are common

MS Office , Lotus Smart Suit , Sun MS Star Office , Corel Word Perfect Office

Other personal application software ? - Personal application software which used for special purposes.

Turbo TAX , CaD

Work-group application software ? - General purpose application that combines a variety of software features and functions to facilitate a collaboration.

Lotus Notes , MS Exchange , Novell Groupware

Enterprise application software ? - Aim to benifit an entire organization by improving cooperation & interaction between all departments and support to supply chain management.

Enterprise Resource Planning (ERP) ? - Manage critical business operations. Even use Small to Medium Enterprises (SMUs) .

Adv. - Eliminating inefficient systems , improved data access for decision making , facilitate adoption of improved work process enable implementation of Supply Chain Management - SCM(To create a fast , efficient , and low cost network of business relationships.)

Dis-Adv. - High cost , employee resistance to change due to change of business process.

Application software for Decision support & specialized purpose ? - These are include expert systems as well as AI applications.

2.4 . Programing Languages & Software

► Overview

People used languages to express ideas each other. Computers are not enough to intelligent for understand the human languages. It can only understandable language is binary language. So programming languages are used for communicate between human and computer. Functions of programming language provide instructions to the computer. Each programming language has a set of keywords , symbols and rules(syntax). Each programming language contains different characteristics or attributes.

Java , Visual Basic , C++ , PASCAL

► Evolution of Programming Language. ? - Users requirement are changed over the years.

First Generation CL ( 1940 s) ? - Use machine language/code , Had to be written in binary notations , depends on its CPU , Tedious & error prone in writing .
Second Generation CL ( 1950 s) ? - Symbols are used to represent operation codes & storage locations , Called as Assembly Languages (Symbolic Language) , These represented symbols converted into machine language using program called Assembler , Complex than high level languages.
Third Generation CL (1960 s) ? - Closer to English than before , Easy to learn , Must to translate these languages into machine languages , Two ways to do this translation.

An Interpreter ? - Interpret one instruction to machine language & execute that , Again interpret next instruction & so on.

Adv. - Easy to debug.

Dis-Adv. - Slow than compile.

Use a compiler ? - Entire high level language translate into machine code and stored in disk. After execute that file.

Adv. - Fast than interpret

Ex. - Java , C++ , Visual Basic

Forth Generation CL ( 1970 s) ? - Very closer to English than 3GLs , minimum codes.

Ex. - SQL

Beyond Fourth Generation CL ? - Used to create AI or expert systems , Also called as natural languages.

Ex. - LISP , ProLog , MYCIN

OOP Languages (Object Oriented Programing) ? - More efficient for programing graphic oriented user interfaces , Re-usability of object

Ex. - SmallTalk , Visual Basic .NET , C++ , Java

Visual Languages ? - Reduce the need to write detailed programming statements.

Ex. - Visual Basic , Visual C++

► Selecting a Programming Language

Batch Vs Real time programing
Procedure Vs Non-Procedure Orientation
PLs for business Vs Scientific Applications
Low productivity Vs High productivity
High error levels Vs Low error levels

2.5. Software Issues and Trends

► Software Bugs ? - Flow in a computer program that causes it to produce incorrect or inappropriate results , In Off-The-Shelf this may high.

► Copyright & Licenses ? - Copyright low gives owner of a work certain rights over it and illegal for the use the work as through they were its owner ,Comes from 18th century , Software vendors earn money through licenses , A license is a permission given by the copyright owner to another person.

Usage based licenses
Capacity based licenses
Software as a network service
Subscription licensing

► Open source Softwares ? - Freely available , Easy to modify , By OSI (Open source Initiative)

Ex. - SendMail , Apache , Linux Free BSD , Perl

More companies are emerging to support to OSI

Ex. - RedHat for Linux , C2Net for Apache

► Software Upgrades ? - Upgrades are provide additional capacities and easy to users.

► Global Software Support ? - Huge companies have distribution problem over the word , This problem overcome by appointing third party distributors , Customers arrange licensing with vendor and third party distributor provide the distribution and support & invoicing services.

**********************************
COMPLETED SECOND LESSON
**********************************

**********************************************************

Click on COMMENTS link to add a comment

**********************************************************

WWW - (01). Introduction To The Internet

2010-02-17T12:29:00.000-08:00

*********************************************************

SORRY FOR THE DELAY . . STILL UPDATING . . . .

*********************************************************

PCA - (01). Introduction to PC Applications

2010-02-16T09:38:00.000-08:00

Applications ? - Computer programs are called as Application software.

Some applications are bundled as packages.

Office Applications

Graphic Design Applications

Web Design Applications

Desktop Publishing Applications

These all applications are running on the special software called Operating System.

Software ? -Computers intangibles called as software.

Operating System ? - The main software that gives a interface for a user to communicate with hardware devices.

Manage hardware devices

Manage and maintain disk file system

Support Applications

Files and Folders in MS Windows

Desktop ? - Very first screen is after login is named as Desktop.

Main Directory of MS Windows ? - My Computer. It has Users document folder , Hard disk drives , Devices with removable storage

Properties in MS Windows

Some uses of Windows Explorer - Create , copy , paste , delete , move (cut and paste) , properties on files or folders

Short cut Keys for Windows Explorer ? -

Files and Folders in Linux

Linux ? - Open source Operating system that started in 1991.

Linux Kernal ? - This and GNU tools use to create different distributions of Linux OSs.

(i) Debian (ii) Slackware (iii) Red Hat

Desktop ? - Desktop is a GUI for communicate with the Kernal.

Ubuntu - gnome desktop (most popular and user friendly)

Kubuntu - kde desktop

Xubuntu - xfce desktop

Main Directory of Linux ? - On Linux main directory starts with / . It has five main directories named etc , dev , home , usr , var

Normal users access only from $HOME directory.

Only super users can modify other directories.

Linux Commands ?

cd change directory
ls list files and folders
mkdir make directory
touch create a file
mv move or rename a file or directory
rm remove
rm -r directory_name(removing directories)
cat display the content of file
vim view a file in new name
cp copy

Linux GUI ? - copy , cut , delete , view properties

Open Office suit ?

OO writer - MS Word

OO Impress - MS Power Point

OO Calc - MS Excel

OO Base - MS Access

Migration of Windows to Linux

Photoshop - GIMP

Win Media Player - MPlayer

3Ds Max - Blender

Dream Viewer - NVU

**********************************

COMPLETED FIRST LESSON

**********************************

**********************************************************

Click on COMMENTS link to add a comment

**********************************************************

CS - (01). Overview of CS

2010-02-16T02:47:00.000-08:00

► Computers ? - Classified as a device that takes in row data as input and process it and provides information as the output.

► Computer Systems ? - Consists of hardware , software , and users that are necessary to make the computer function and to process data in a meaningful way and store data.

► Computer Hardware

Processor - Brain of the computer.It connect all other components.

Intel - Pentium , Celoron , Xeon

AMD - Duron , Athlon

Sun - SPARC

Centaur - Cyrix

IBM - PowerPC

Motorola - Motorola6800

Memory - Internal storage areas in a computer.

I/O Devices

Input - Keyboard , Mouse , Trackball , scanner

Output - Monitors , Projectors , Printer , speakers

I/O - Joystick , Touch Screen display

Storage Devices - Magnetic tapes , Floppy disks , Hard disks , ZIP disks , CD , DVD , BD , Flash drives , Memory cards

Expansion Cards - VGA(Video Graphics Adaptor) cards , Sound cards , Ethernet cards , TV cards , Data FAX modem cards , USB cards , Fire wire

Others - IrDA(Infra Red) , Blue Tooth , Wi Fi

Chassis - Cover and bays to hold components in computer.

ATX Tower

- Mini Tower

- Mid – size Tower

- Full – size Tower

Desktop

- Desktop Flatbed

- Slim desktop Flatbed

Drive Bays

3 inch Bay - Hard disks , Floppy disks

5 inch Bays - CD drives , DVD drives

Power Supply

In -(110V or 230V) Out - (-12V) to (12V)

Power Connectors

Mini Plug - Floppy drives

Molex - Hard disks , CD DVD drives , SCSI(Small Computer System Interface) drives

12V ATX - Mother board

SATA - SATA (Serial Advanced Technology Attachment) Hard disks , SATA CD DVD drives

Buttons And Indicators

► Evolution of Computers

Mechanical Computer to UNIVAC

Mechanical Computer ?

By - Charles Babbage

In - 1822

Input - punch card

Control Unit - Control or program processor

A Processor - Calculate or Process

Storage - 50 digits X 1000

Output device - Can print final results

UNIVAC ?

By -John Mauchly and J. Prespe Eclert

In - 1947

1st time RAM implement

Program by mathematical language

Both alphabetical and numeric programs

► Modern Day Computers

Super Computers ? - Most powerful computers , thousands of micro processors , sophisticated , expensive computers

Usage : Weather , Chemical Process , US economic predictions , universities , resercher organizations

Mainframe Computers ? - Large powerful systems , users connect and access resources through called terminal , terminals divide into dumb and intelligent ,can handle even more than thousands users at a time , handle a particular task.

Usage : Bank systems , Air line reservations , motor vehicle departments

Mini Computers ? - Less powerful than mainframes , more powerful than personal computers , can handle hundreds of users at a time , small than mainframes , can connect terminals and personal computers

Usage : Libraries , Large stocks

Network Servers ? - If set of computers are interconnect as network , there is a main computer named server for manage and supervise that network. It can share files , printers , internet , emails , databases and etc . .

Usage : As email servers , Proxy servers , File servers , Printer servers , Database servers

Personal Computers ? - Individual users , Small size , ability to act as general purpose machine.

Usage : To send emails , Surf Internet , Document creates , Play games , Hear songs

► Von Neumann Architecture ? - Is a design model for a stored-program digital computer that uses a central processing unit(CPU) and a single separate storage structure(memory) to hold both instructions and data. It named after the mathematician and early computer scientist John von Neumann. Such computers implement a universal tuning machine and have a sequential architecture.

**********************************

COMPLETED FIRST LESSON

**********************************

**********************************************************

Comments are welcome

Click on COMMENTS link to add a comment

**********************************************************

IS - (01). Introduction To IS

2010-02-09T20:34:00.000-08:00

► Data ? - Set of facts which describe a particular things in the real world.

♥ employer name , address , nic

► Information ? - Kind of data which will useful for decision making in different contexts.

♥ salary of month

►Process ? - Series of activities for convert Data into Information.

♥ calculate presence , calculate deductions

►Characteristics ? - V . . . FAST RACERS

V-erifiable

F-lexible

A-ccurate

S-imple

T-imeliness

R-eliable

A-ccessible

C-omplete

E-conomical

R-elevant

S-ecure

►System ?- means a collection of components which work together to achieve a specific goal.
♥ Human Body , School
Concepts

►System Types ? - S O A P S

S-imple Vs Complex
O-pen Vs Close
A-daptive Vs Non Adaptive
Permenent Vs Temporary
Stable Vs Dinamic

►System Performance Indicators ? - E E

E-fficiency
E-ffectiveness

► System Variables ? - Control by decision makers.

►System Parameters ? - Values that can't control by decision makers.

►Modelling ? - simplify presentation of such complex things in real world.

► Models Classification ? - N S P M

N-arrative
S-chematic
P-hysical
M-athematical
►Information Systems ? - Set of interrelated components that collect (input), manipulate & store (process) , disseminate (output) data and information and provide a feedback.

►Main component of IS - I O P F
I-nput
P-rocess
O-utput
F-eedback

►Computer Based IS (CBIS) - Single set of hardware , software , database , telecommunications , people & procedures that are configured to collect , manipulate , store , and process data into information.

►Activities in IS

Input of data resources
Processing of data into information
Output of data resources
Storage of data resources
Control of system performances

►Trends in IS

►Role of IS

Support its business process and operations.

Support decision making by its employees and managers.

Support its strategies for competitive advantage.

►Management challenges

Success and failure with IT

IS solution development challenges

Challenges of ethics and IT

Human resources challenges

►Important of learning IS - All the types of companies are use IS to various useful reasons.

Computer literacy and IS literacy are must.

IS Careers

Primary responsibilities of IS company are operations , system development and support.

Skills required by IS personnel

**********************************

COMPLETED FIRST LESSON

**********************************

**********************************************************

Comments are welcome

**********************************************************