notes to review-ics3

8/14/2019 Notes to Review-ics3

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NOTES TO REVIEW:

part 1- intro

HISTORY:

1991

James gostlingSun Microsystems

Oak

Motivation- platform independent language embedded in objectsPersonal hand held remote-star 7

JAVA TECHNOLOGY(pdad)

Programming languageDevelopment

Application

Deployment

DEVELOPMENTJavac (complier)

Interprester (java)

Documentation generator (javadoc)

Class file packaging tool

APPLIC AND RUNTIME

JRE- java runtime environment

DEPLOYMENT(2)SDK-software development kitWeb browser

JAVA FEATURESJVM- java virtual machine

Garbage collection

Code security

JVM

Imaginary machine, compile java codes

Bytecode- cde understood by all JVM

GARBAGE COLLECTION

Frees any memory auto

CODE SECURITY

JRE-perform class loading, code verification and code execution.

Class loader-


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Bytecode verifier

SummaryJava Background HistoryJava Technology A programming language, developmentenvironment, application environmentand deployment environment

Java FeaturesJava Virtual machine, garbage collection and codesecurity

Phases of a Java Program Write, compile, run

part 3- getting to know your programming environment

CONSOLE

Where to type in commands (terminal, MSDOS command prompt)

TEXT EDITOR

Notepad, wordpas, vi


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IDE (INTEGRATED DEVELOPMENT ENVIRONMENT)

GUI builder, text/ code editor, compiler, interpreter, debugger

ERRORS: SYNTAX AND RUN-RUNTIME

SYNTAXTyping errors- misspelled/ forgot semi colon

RUNTIMEDisplay only when run or when logical processes are incorrect

Summary

My First Java Program Using a Text Editor and Console Write program Compile program Run program

Errors Syntax Errors Runtime Errors

part 4-programming fundamentals

CLASS

CURLY BRACEStart of block

COMMENT

Document part of code

MAIN METHOD

Starting point of java (all except applets)


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public static void main(

String[] args ){

PRINT TEXT

System.out.println();

System.out.print();

JAVA EXTENSIONS

File name should match class

JAVA COMMENTS (3)- DELIMITERS

C++ (//) single line

C (/* */) multiple lines

JAVADOC (/** */) can contain tags

STATEMENTS

Lines of code terminated by (;)

BLOCK

Statements counded by cruly braces

IDENTIFIERS

Tokens that represent variables, methods, classes etc. (Hello, main, System, out)Case sensitive

Begin with: letter, _, $, upper/lowercase, 0-9.

Cannot use: class, public, void (keywords)

CLASSES AND METOHDS

c- all caps first letter (HelloWorld)

m- small cap first letter (helloWorld)

*multiword- charArray, ClassName

*avoid- underscore at start

KEYWORDSPredefined and reserved for a purpose

Not for identifiers


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LITERALS

Non-changing tokens (constant)

Types:

IntegerFloating point

Boolean

Character

String

INTEGER

Decimal (12)

Hexadeximal (0x12)

Octal (012)

FLOATINGRepresent decimal/fractions

Standard (3.45) or scientific (3.45e2) notation

BOOLEAN

true/ false

CHARACTER

Single Unicode (16 bit) which allows inclusion of symbols, special characters from

other languages

Quote delimiter (a)

\n, \r, \b- newline, carriage return, backspace

STRING

Represent data type containing Multiple characters ( ).

Not data type but CLASS

DATA TYPES PRIMITIVE AND REFERENTIAL


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PRIMITIVE (8)

Boolean (logical)

Char (textual)

Byte

Short

IntLong

Double

Float

INTEGRAL

Byte, short, int, long

Used in 3 forms (decimal, octal, hexadecimal)

Int- default

L-long value

FLOATING POINT

Float and double

Double-default

e-exponential

VARIABLE

an item of data used to store the state of objects

*data type- indicates the type of value to be hold (int, char)


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*name, must be followed for identifiers

TYPES OF VARIABLES-primitive (int, long)- actual memory location

-reference () stores address in memory location

OPERATORSArithmetic

Relational

Logical

Conditional

(all follow a precedence for the compiler to evaluate frist)

ARITHMETIC

Increment (++)

Decrement (--)


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(RELATIONAL)

Compare, evaluate and relate two values

There are six logical operators: && (logical AND)

& (boolean logical AND) || (logical OR) | (boolean logical inclusive OR) ^ (boolean logical exclusive OR) ! (logical NOT)


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Truth tables:&& AND &

&& (logical) & (Boolean logical)

&&- short circuit evaluations (partial)

&-not partial(evaluates both)

Truth table for || and |

(same as above)

^- bollean logical exclusive OR)

s


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The result of an exclusive ORoperation is TRUE, if and only

if one operand is true and theother is false. Note that both operands mustalways be evaluated in orderto calculate the result of anexclusive OR.

Truth table for !

**takes in one argument (variable, expression, constant)

LOGICAL: CONDITIONAL OPERATORS (?:)(?)-ternary operator which takes in 3 arguments to forma conditional expression


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Summary


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Java Comments (C++-StyleComments, C-Style Comments,

Special Javadoc Comments)Java statements, blocks,identifiers, keywordsJava Literals (integer, floatingpoint, boolean, character,String) Primitive data types( boolean,char, byte, short, int, long,float, double)

5-GETTING INPUT FROM THE KEYBOARD

BufferedReader AND JOptionPaneClasses used to get input from keyboard USING:BR-console

JOP-GUI

BUFFEREDREADER

1.Java.io package (import java.io.*;)

OR

import java.io.InputStreamReader;

import java.io.IOException;

2.BufferedReader dataIn = new

BufferedReader( new

InputStreamReader(System.in) );3. TRY CATCH BLOCK (temporary string to get input )


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try{

String temp = dataIn.readLine();

}catch( IOException e ){

System.out.println(Error in getting

input);

}

**API- application programming interface

Containes presdefined classesPackages conatin classes with related purpose

JOPTION PANE- pop up dialog box1. javax.swing (import javax.swing.*;)

6-CONTROL STRUCTURES

Decision (if,else, switch)

Repetition (while, do-while, for)

Branching statements (break, continue, return)

CONTROL STRUCTURES

Can change ordering of statements in programTwo types:DECISION- select specific areas to be exe

REPETITION- exe specific areas a number of times

DECISION

If


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If-else

If-else-if


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SWITCHBranching on multiple outcomes


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REPETITION

While

Do-while

For

BRANCHING STATEMENTSRedirect flow of program

BREAK

Unlabeled- terminates enclosed statementLabeled terminates out statement


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CONTINUE

Unlabeled- skips to end of innermost loop

Labeled skips to out loop

RETURNExit the current method

7-JAVA ARRAYS

ARRAY

Stores multiple data tiems of same data type in a block of memory divided in slots

DECLARING ARRAY

Int arr [ ];

INSTANTIATION

Create araay*constructor-method to create certain object

Int arr [ ]= new int [100];


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ACCESSING ARRAY

Index/ subscript-

notes to review-ics3

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