hssn language translator
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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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CT014-1 Hardware, Systems Software and Networks Chapter 2 3
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 5
Low-Level LanguagesWhat is machine language?
Only language computer
directly recognizes
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CT014-1 Hardware, Systems Software and Networks Chapter 2 6
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
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Procedural Languages What is a compiler?
Program that
converts entiresource program
into machine
language before
executing it
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Procedural LanguagesWhat is an interpreter? Program that
translates andexecutes one
program code
statement at
a time Does not produce
object program
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Procedural LanguagesWhat is BASIC?
Designed for use as simple, interactive problem-solving
language
Beginners All-purpose Symbolic Instruction Code
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Procedural LanguagesWhat is COBOL?
Designed for business applications
English-like statements make code easy to read, write,
and maintain COmmon
Business-Oriented
Language
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Procedural Languages What is C? Powerful language originally designed to write system
software
Requires professional programming skills
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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
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Object-Oriented Programming Languages
What is C++? Includes all elements of C, plus additional features
for working with object-oriented concepts
Used to develop
database and
Web applications
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Object-Oriented Programming Languages
What is Java?
Developed by Sun
Microsystem
Similar to C++ but
usesjust-in-time (JIT)
compilerto convert
source code intomachine code
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Object-Oriented Programming Languages
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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Object-Oriented Programming Languages
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.
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Object-Oriented Programming Languages
What is Delphi? Powerful visual programming tool
Ideal for large-scale enterprise and Web applications
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CT014-1 Hardware, Systems Software and Networks Chapter 2 19
Object-Oriented Programming Languages
What is PowerBuilder?
Another powerful visual programming tool
Best suited for Web-based and large-scale
object-oriented applications
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CT014-1 Hardware, Systems Software and Networks Chapter 2 20
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 21
Nonprocedural Languages
and Program Development ToolsWhat is RPG(Report Program
Generator)? Nonprocedural language used for generating reports,performing computations, and updating files
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CT014-1 Hardware, Systems Software and Networks Chapter 2 22
Nonprocedural Languages
and Program Development Tools
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 23
Nonprocedural Languages
and Program Development Tools
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 24
Nonprocedural Languages
and Program Development Tools
What is Visual Basic for Applications
(VBA)? Macro programming language Macroseries of statements used to automate tasks
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CT014-1 Hardware, Systems Software and Networks Chapter 2 25
Web Page DevelopmentWhat is HTML (Hypertext Markup Language)? Used to create Web pages
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CT014-1 Hardware, Systems Software and Networks Chapter 2 26
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 27
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 28
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 29
Web Page DevelopmentWhat is dynamic HTML (DHTML)?
Allows developers to
include more graphical
interest and interactivity
in Web page
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CT014-1 Hardware, Systems Software and Networks Chapter 2 30
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 31
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 32
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 33
Other Programming LanguagesWhat are other available programming
languages?
ALGOLADA APL
FORTH LISPHYPERTALKFORTRAN
LOGO PASCALMODULA-2
PILOT SMALLTALKPROLOGPL/I
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CT014-1 Hardware, Systems Software and Networks Chapter 2 34
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 35
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 36
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 37
Step 2 Design SolutionWhat is a hierarchy chart? Shows program modules graphically Also called structure chart
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CT014-1 Hardware, Systems Software and Networks Chapter 2 38
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 39
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 40
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 43
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 45
Step 2 Design Solution
What is flowcharting software? Used by programmers to develop flowcharts
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CT014-1 Hardware, Systems Software and Networks Chapter 2 46
Step 2 Design SolutionWhat is pseudocode?
Uses condensed form
of English to convey
program logic
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CT014-1 Hardware, Systems Software and Networks Chapter 2 47
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 48
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 49
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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CT014-1 Hardware, Systems Software and Networks Chapter 2 50
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