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Hardware and Software Systems and Networks 2CT024-3-2

Degree : Level-2

Language Translator


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CT014-1 Hardware, Systems Software and Networks Chapter 2 2

Objectives

Differentiate between machine and assembly languages

Identify and discuss the purpose of procedural programminglanguages

Discuss the advantages and uses of visual programming languages

Identify and discuss the characteristics of object-oriented

programming languages Identify the uses of various nonprocedural languages and tools

Describe various ways to develop Web pages including HTML,scripting languages, DHTML, XML, WML, and Web page authoringsoftware

Identify the uses of popular multimedia authoring programs

List the six steps in the program development cycle Differentiate between structured design and object-oriented design

Explain the basic control structures used in designing solutions toprogramming problems


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Computer Programs and

Programming Languages

What is a computer program? Set of instructions that directs computer to perform

tasks Programming languageused to write instructions


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Low-Level LanguagesWhat is machine language?

Only language computer

directly recognizes


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Low-Level LanguagesWhat is assembly language? Instructions made up of

symbolic instruction

codes, meaningfulabbreviations and codes

Source programcontains

code to be converted to

machine language


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Procedural LanguagesWhat is a procedural language?

Most widely used are BASIC,

COBOL, and C

Uses series of English-like

words to write instructions

Often called third-generation

language (3GL)

Programmer writesinstructions that tell

computer what to accomplish

and how to do it



Procedural Languages What is a compiler?

Program that

converts entiresource program

into machine

language before

executing it



Procedural LanguagesWhat is an interpreter? Program that

translates andexecutes one

program code

statement at

a time Does not produce

object program



Procedural LanguagesWhat is BASIC?

Designed for use as simple, interactive problem-solving

language

Beginners All-purpose Symbolic Instruction Code



Procedural LanguagesWhat is COBOL?

Designed for business applications

English-like statements make code easy to read, write,

and maintain COmmon

Business-Oriented

Language



Procedural Languages What is C? Powerful language originally designed to write system

software

Requires professional programming skills



Object-Oriented Programming Languages

What is an object-oriented programming

(OOP) language?Used to

implement

object-oriented

design

Major benefitis ability to

reuse existing

objects

Event-drivenchecks for

and responds

to set of events

C++ and Javaare complete

object-oriented

languages

Objectis

item thatcontains

data and

procedures

that act on

data

Eventisaction to

which

program

responds




What is C++? Includes all elements of C, plus additional features

for working with object-oriented concepts

Used to develop

database and

Web applications




What is Java?

Developed by Sun

Microsystem

Similar to C++ but

usesjust-in-time (JIT)

compilerto convert

source code intomachine code




What is a visual programminglanguage?

Programmer writes

and implements

program in segments

Visual programming

environment (VPE)

allows developers to

drag and drop objectsto build programs

Often used in RAD

(rapid application

development)

environment

Sometimes called

fifth-generation

language

Provides visual or

graphical interface for

creating source code


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What is Visual Studio .NET 2003? Suite of visual programming languages and RAD tools .NET is set of technologies that allows program to run on Internet

Visual Basic .NET 2003is used to build complex object-based programs

Step 1. Theprogrammer

designs the

user interface.

Step 2.The programmerassigns properties to each

object on the form.

Step 4.The programmer

tests the application.

Step 3.The

programmerwrites code

to define the

action of each

command button.




What is Delphi? Powerful visual programming tool

Ideal for large-scale enterprise and Web applications


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What is PowerBuilder?

Another powerful visual programming tool

Best suited for Web-based and large-scale

object-oriented applications


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Nonprocedural Languages

and Program Development Tools

What are nonprocedural languagesand

program development tools?

Nonprocedural

LanguageThe programmer writes English-

like instructions or interacts with

a visual environment to retrievedata from files or a database

Program Development

ToolsUser-friendly programs

designed to assist both

programmers and users increating programs


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and Program Development ToolsWhat is RPG(Report Program

Generator)? Nonprocedural language used for generating reports,performing computations, and updating files


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What is a fourth-generation language

(4GL)? Nonprocedural language that allows access to data indatabase Popular 4GL is SQL, query language that allows users to

manage data in relational DBMS


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What is an application generator? Program that creates source code or machine code from

specification

Consists of report writer, form, and menu generator

Formprovides areas for entering data


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What is Visual Basic for Applications

(VBA)? Macro programming language Macroseries of statements used to automate tasks


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Web Page DevelopmentWhat is HTML (Hypertext Markup Language)? Used to create Web pages


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Web Page DevelopmentHow are special effects and interactive elementsadded to a Web page?

Countertracks

number of

visitors to

Web site

Image mapgraphic

image that

points to

URL

Scriptinterpreted

program that

runs on client

Appletusually runs

on client, but

is compiled

Processingform

collects data

from visitors

to Web site

Servletapplet that

runs on

server

ActiveX

control

small program

that runs on

client


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Web Page DevelopmentWhat is the common gateway interface (CGI)? Communications standard that defines how Web server

communicates with outside sources

Step 3. When the user submits arequest, it is sent to the CGI program.The CGI program contacts the

database and requests information for

the user. In this case, it looks for a

movie titled The Wizard of Oz.

Step 1. Theprogrammer stores

the CGI program in

a special folder on

the Web server such

as /cgi-bin.

Database

CGI scriptprogramthat manages sending and receiving across CGI

Step 2. The Webmaster creates alink between the CGI program andWeb page. When a user displays the

Web page, the CGI program

automatically starts.

Step 4. The CGIprogram receives

information from the

database, assembles

it in an HTML

format, and sends it

to the users Web

browser.


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Web Page DevelopmentWhat is a scripting language? Typically easy to learn and use

JavaScriptadds

dynamic content and

interactive elements to

Web page

VBScript (Visual Basic,

Scripting Edition)adds

intelligence and

interactivity to Web page

Perl (Practical Extractionand Report Language)

has powerful text

processing capabilities


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Web Page DevelopmentWhat is dynamic HTML (DHTML)?

Allows developers to

include more graphical

interest and interactivity

in Web page


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Web Page DevelopmentWhat are XHTML, XML, and WML?

XHTML

(ExtensibleHTML)enables Web sites to be displayed

more easily on microbrowsers

XML

(ExtensibleMarkupLanguage)allows developers to

create customized tags

WML

(WirelessMarkupLanguage)allows developers to design pages

specifically for microbrowsers

Includes features of HTML

and XML

Uses wireless

application protocol (WAP),

standard that specifies

how wireless devices

communicate with Web

Server sends entire record to

client, enabling client to do

much of processing without

going back to server


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FrontPage

2003

Flash

MX

Web Page DevelopmentWhat is Web page authoring software?

Creates sophisticated Web pages without using HTML Generates HTML

Dreamweaver

MX


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Multimedia Program

DevelopmentWhat is multimedia authoring software?

Combines text,

graphics, animation,

audio, and video intointeractive presentation Used for computer-

based training (CBT)

and Web-based training

(WBT)

Software includes

Toolbook, Authorware,

and Director


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Other Programming LanguagesWhat are other available programming

languages?

ALGOLADA APL

FORTH LISPHYPERTALKFORTRAN

LOGO PASCALMODULA-2

PILOT SMALLTALKPROLOGPL/I


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The Program Development CycleWhat is the program development cycle?

Steps programmers use to build computer programs

Programming

teamGroupof

programmersworking on

program


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Step 1 Analyze RequirementsWhat is involved in analyzing the

requirements?1. Review requirements2. Meet with systems analyst and users3. Identify input, output, processing, and data

components

IPO chart

Identifies

programs inputs,outputs, and

processing steps


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Programmer

begins with general

design and moves toward

detailed design

Step 2 Design SolutionWhat is involved in designing the solution?

Object-oriented

design

Structured

design, sometimes

called top-down design

Two

approaches

Devise

solution

algorithm,

step-by-stepprocedure to

solve problem


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Step 2 Design SolutionWhat is a hierarchy chart? Shows program modules graphically Also called structure chart


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Step 2 Design Solution What is object-oriented (OO) design? Programmer packages data and

procedure into single unit, an object Objects are grouped into classes Class diagramrepresents hierarchical

relationships of classes graphically


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Step 2 Design Solution What is a sequence control structure? Control structure that shows actions following each

other in order

Control structuredepicts logical order of programinstructions


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Step 2 Design SolutionWhat is a selection control structure?

Tells program which

action to take, based

on a certaincondition

Two types Case control structure

If-then-else controlstructureyieldsone

of two possibilities:

true or false


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Step 2 Design SolutionWhat is a case control structure? Yields one of three or more possibilities


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Step 2 Design Solution

What is a repetition control structure? Enables program to perform one or more actions

repeatedly

Do-while controlstructurerepeatsas

long as condition is

true

Do-until control

structurerepeatsuntil condition is true

Do-While Control Structure Do-Until Control Structure


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Step 2 Design Solution What is aprogram flowchart? Graphically shows logic

in solution algorithm


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Step 2 Design SolutionWhat is an example of a flowchart?


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Step 2 Design Solution

What is flowcharting software? Used by programmers to develop flowcharts


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Step 2 Design SolutionWhat is pseudocode?

Uses condensed form

of English to convey

program logic


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Step 3 Validate DesignWhat is involved in validating the design?

Check program

design for accuracy

Logic error

design flaw

that causes

inaccurate results

Test data

sample data that

mimics real data that

program will process

Programmer checkslogic for correctness

and attempts to uncoverlogic errors

Desk checkprogrammers use test

data to step through logicStructured walkthrough

programmer explains

logic of algorithm while

programming team steps

through program logic


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Step 4 Implement Design What is implementation? Writing the code that translates the design into a program

Syntaxrules that specify how to write instructions

Commentsprogramdocumentation

Extreme programming (XP)coding and testing as soon as

requirements are defined


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Step 5 Test SolutionWhat is involved in testing the solution?

Ensure program runs correctlyand is error free

Debugginglocating and

correcting syntax and logicerrors, orbugs

Test copy of program,

called beta, sometimes

used to find bugs


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Step 6 Document SolutionWhat is involved in documenting the

solution? Programmer performs two activitiesReviews program

coderemoves dead

code, program

instructions that

program never executes

Reviews

documentation

S f L


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Summary of Language

Translators

Various programming languages

used to write and develop computer

programs The program development cycle and

the tools used to make this process

efficient Web development and multimedia

development tools

Documents

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