Computing Fundamentals Slides

8/19/2019 Computing Fundamentals Slides

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Computer Fundamentals


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Course Plan Basic Understanding


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Muhammad Asim Rehmat MS Computer Science in Artifcial Intelligence, UET

Lahore, B.S. in CSE UET Lahore. Ph! in Automation.. Thesis in progress Belongs to SIAL"#T $ot %irst pri&es in man' (ational)International

so*t+are)hard+are competitions !eelopment o* PA" Linu- at UET an' man' e

$oernment pro/ects $ot more than 01 %irst pri&es in All Asia and All

Pa2istan Engineering So*t+are Competitions asPro/ect Adisor

Su3/ects Taught so *ar4 5o3otics C(C Machines, Em3edded S'stems,

Industrial Automation, Control S'stems, ArtifcialIntelligence, !L!, (umerical Anal'sis etc


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La3 Per*ormance 617 Personal)Pro*essional $ro+th 017 Term Pro/ect 817 Mids 017 %inal 617


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How is a computer defined?

Electronic device operating under the control

of instructions stored in its own memory A computer is an electronic machine that

takes input from the user , processes thegiven input and generates output in the form

of useful information. An electronic device that receives data,

processes data, stores data, and produces aresult (output).


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Computers areeverywhere

In usiness

In !u"lication #ield

In Education #ield

In $overnment %rgani&ations

In 'edical #ield

In cience #ield

In Entertainment #ield


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A computer has high speed of calculation,

diligence, accuracy, relia"ility, or versatilitywhich made it an integrated part in all

"usiness organi&ations.

!ayroll calculationsudgetingales analysis

#inancial forecasting'anaging employees data"ase'aintenance of stocks etc.

Business


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oday "anking is almost totally dependent

on computer. anks provide followingfacilities*

anks provide online accounting facility,

which includes current "alances, deposits,

overdrafts, interest charges, shares, and

trustee records.

A' machines are making it even easierfor customers to deal with "anks

Banking


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+omputers are "eing vastly used in

education*

Admission systemsEamination-i"raryesearch pu"licationsimulation softwares

Education


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+omputers are "eing vastly used in

education*Advertising / 0ith computers, advertising

professionals create art and graphics, write

and revise copy, and print and disseminateAt Home hopping / Home shopping has

"een made possi"le through use of

computeri&ed catalogues that provide

access to product information and permitdirect entry of orders to "e filled "y the

customers.

Sales and Marketing


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%ne of ma2or areas is +A1 (+omputer aided

design). hat provides creation andmodification of images. ome fields are:tructural Engineering / Requires stress andstrain analysis for design of Ships, Buildings, cars,

Airplanes etc.

Industrial Engineering / Computers deal withdesign, implementation and improvement of integrated

systems of people, materials and equipment.

Architectural Engineering / Computers help inplanning towns, designing buildings, determining a

range of buildings on a site using both ! and "!

drawings.

Engineering Design


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+omputers are largely used in armies

'issile +ontrol'ilitary +ommunication'ilitary %peration and !lanningmart 0eapons

Military


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ome main areas in this category are*

E/mail+hattingocial 3etworking4ideo/conferencingmart phones

Communication


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he uni5ue capa"ilities and characteristicsof a computer are*

peedtorage capacityAccuracyelia"ility4ersatility

Capailities


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!nput devices "utputdevices

Storagedevices

C#$ Memory


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9.9. Input !eices :"e'3oard, Mouse, etc.;Input !eices :"e'3oard, Mouse, etc.;

ideo Card, Sound Card, or

(IC;(IC;

8.8. ?ard !rie Ports and Connections :USB,?ard !rie Ports and Connections :USB,

%ire+ire, etc.;%ire+ire, etc.;


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MouseMouse

"e'3oard"e'3oard

MicrophoneMicrophone

ScannerScanner

@e3cam@e3cam


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Monitor

Printer

Spea2er)?eadphone


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A deice that interprets and runs thecommands that 'ou gie to the computer.

Also re*erred to as the processor.

T+o ma/or 3rands are Intel and AM!.

E-amples4 Intel Core < !uo, AM! Turion <


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Memor' is +here in*ormation is stored andMemor' is +here in*ormation is stored and

retrieed 3' the CPU.retrieed 3' the CPU.

There are t+o main t'pes o* memor'4 There are t+o main t'pes o* memor'4

◦ 5andom Access Memor' :5AM;4 It is the5andom Access Memor' :5AM;4 It is the

main memor' and allo+s 'ou tomain memor' and allo+s 'ou to

temporaril' store commands and data.temporaril' store commands and data.

◦

5ead #nl' Memor' :5#M;4 It is the5ead #nl' Memor' :5#M;4 It is thememor' that retains its contents eenmemor' that retains its contents een

a*ter the computer is turned o.a*ter the computer is turned o.


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o Is the main circuit "oard inside the computer.Is the main circuit "oard inside the computer.

o Has tiny electronic circuits and otherHas tiny electronic circuits and other

components on it.components on it.

o +onnects input, output, and processing+onnects input, output, and processing

devices together (+!6, 'emory, Hard 1rive,devices together (+!6, 'emory, Hard 1rive,

141 1rive)141 1rive)

o ells the +!6 how to run.ells the +!6 how to run.


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>ideo Card is connected to the computer>ideo Card is connected to the computermonitor and is used to displa' in*ormationmonitor and is used to displa' in*ormationon the monitor.on the monitor.

(et+or2 Inter*ace Card :(IC; is connected(et+or2 Inter*ace Card :(IC; is connectedto other computers so that in*ormation canto other computers so that in*ormation can3e e-changed 3et+een them.3e e-changed 3et+een them.

Sound Card conerts audio signalsSound Card conerts audio signals:microphone or audio tape; +hich can 3e:microphone or audio tape; +hich can 3estored as a computer audio fle.stored as a computer audio fle.


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?ard !is2?ard !is2

%lash !rie%lash !rie

C!5#MC!5#M

!>!5#M!>!5#M


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Uniersal Serial Bus :USB; PortUniersal Serial Bus :USB; Port

%ire@ire :similar to USB 3ut *aster;%ire@ire :similar to USB 3ut *aster;

(et+or2 Port :Ethernet;(et+or2 Port :Ethernet;

Parallel Port and Serial PortParallel Port and Serial Port

!ispla' Adapter!ispla' Adapter

Po+erPo+er


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The intangi3le set o* instructions that tellsthe computer +hat to doD 2no+n asprograms or so*t+are programs.


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#perating S'stem So*t+are◦ Sets the rules *or ho+ computer hard+are and

application so*t+are +or2 together, controls theoperation o* the computer. E-ample4 @indo+s

Application So*t+are◦ Lets 'ou accomplish specifc tas2s 3ased on 'our

needs. E-amples4 MS @ord, E-cel, Access, MS @or2s


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Boots :starts up; the computer %ormats dis2s Creates *olders

Saes and retriees fles Moes and copies fles

Eer' Computer ?as #perating S'stem

So*t+are


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So*t+are that +or2s +ith the operating s'stem to meet aspecifc need or per*orm a specifc tas2

E-amples4

MS @ord

MS E-cel

MS Po+erPoint

Internet E-plorer


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@ord Processing◦ Program that allo+s 'ou to create, edit, and print

te-t documents 5eport, F'er, memo

Spreadsheet◦

(um3ered 5o+s and Lettered Columns◦ Intersection o* a ro+ and column is a cell $rade 3oo2, fnancial in*o

!ata3ase◦ Lets 'ou set up an electronic fling s'stem◦ Enter te-t and num3ers %ind, search, and print in*o in dierent +a's

Address 3oo2, Card Catalog


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0<

Humanlanguage

#rgramming language

Computerlanguage

C*

*(+ava(,C(,B(-.et(C/

compiler

I +ant to add one andone

9G9 191199191199

"peratingSystem


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@hat is a net+or2H

""

One type is

a modem

Enables a

connection

betweencomputers

Enables a

connection

between

computers

Cables

Cellular

radio

Telephone

lines

Satellites

CommunicationsMedia

Communications

Media

Communications

Device

Communications

Device

Collection of computers and devices connected together


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@h' do +e need net+or2H

"#

To shareTo share

ResourcesResources

Hardware

devices

Hardware

devicesSoftware

programs

Software

programs

DataDataTo save

timeand

money

To save

timeand

moneynformationnformation


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@hat is a sererH

"

Manages the

resources on

a networ!

" client accesses

the resources

on the server


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@hat is the InternetH

"

#orldwide collection of networ!s that connects

millions of computers


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"

#hy do users access the nternet$

%& nformation

'& Shopping

(& )an!ing and nvesting*& Classes

+& Entertainment

,& Communications


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?o+ do 'ou install and run a so*t+are programH

"

tep 7.nsert the program

disc into the CD0

ROM drive

tep 8. nstall the

software program byinstruction in the disc.

then run the program

tep 9.

The program e-ecutes

" program is a series of instructions that tells the

computer what to do


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@hat is a graphical user inter*ace :$UI;H

#

"llows you to interact with the software

using graphics and icons

Controls how you enter data and how the

screen displays information


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@hat is s'stem so*t+areH

#

Operating System 1OS2Operating System 1OS2is a set of programs

that coordinates all

activities among

computer hardware

devices and allowsusers to run

application software

Operating System 1OS2Operating System 1OS2is a set of programs

that coordinates all

activities among

computer hardware

devices and allows

users to run

application software

3tility 4rograms3tility 4rograms allow the user toperform maintenance0type tas!s

usually related to managing a

computer. its devices or its programs

3tility 4rograms3tility 4rograms allow the user toperform maintenance0type tas!s

usually related to managing a

computer. its devices or its programs

4rograms that control the operations of the computer

and its devices


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@hat is application so*t+areH

#

4resentation5raphics

Spreadsheet

Database

#ord

4rocessing

4rograms that perform specific tas!s for users Suite

4opular software applications

bundled together as a single unit


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@hat is a programmerH

#

Someone who develops application or system software

4rogrammer writes instructionsto direct computer to processdata into information


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#

#hat are the categories of computers$

!ersonal computers (desktop)'o"ile computers and mo"ile

devices'idrange servers'ainframe computers

upercomputers


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@hat are the t+o most popular series o*

personal computersH

#

4C and compatibles

use the #indows

operating system

"pple Macintosh

uses the Macintosh

operating system1Mac OS2


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@hat is a des2top computerH

#

Designed so all of the components fit on or under

a des! or table


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@hat is a note3oo2

computerH

#&

4ortable. small enough to fit on

your lap1% lbs to 6 lbs 2

"lso called a laptop

5enerally more e-pensive than

a des!top computer


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@hat is a ta3let PCH

#'

Resembles a letter0si7ed slate "llows you to write on the screen

using a stylus

Smaller version is the modularcomputer

#hat are #eb0enabled handheld computers$

"llow you to chec! e0mail and access the nternet 0e"/ena"led telephone is a :smart phone;


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@hat is a personal digital assistant :P!A;H

#(

4rovides personal organi7er functions

Calendar

"ppointment boo! "ddress boo!

Calculator

8otepad


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@hat t'pes o* serers are thereH

$)

Midrange server 4owerful. large

computer that supports up to a few

thousand computers

Mainframe 9ery powerful.e-pensive computer that supports

thousands of computers

Supercomputer The fastest. most

powerful. most e-pensivecomputer& Used for applications

requiring complex mathematical

calculations


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@hat are fe categories o* computer usersH

$

Home mall %ffice<

Home %ffice (%H%)

'o"ile

-arge usiness !ower


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@hat so*t+are is aaila3le *or a home userH

$

• Web access

• Entertainment

• Communications

• Personal finance management


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@hat so*t+are is aaila3le *or a small

oce)home oce :S#?#; userH

$

:ocal area networ! 1:"82

4roductivity software

Specialty software

#eb usage

E0mail


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@hat is aaila3le *or

a mo3ile userH

$

Hardware

Software

4roductivity 4resentation

4ersonal

information

manager

3ote"ook

computers

Handheld computers

0e"/ena"led

cellular phones


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@hat are the needs o* the large 3usiness userH

$

#eb access 4ublic !ios! Telecommuting 8etwor! 4roductivity software

Scheduling


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@hat are the needs o* a po+er userH

$

Speed and large amounts of storage

Types of power users

Engineers

"rchitects

Des!top publishers

5raphic artists


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@hat are some e-amples

o* computer applicationsin societ'H

$

Education ;inance

5overnment Healthcare Science

4ublishing

Travel ndustry


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@hat are in*ormation s'stem elements H

$

4eople 4rocedures Data Software

Hardware

tep 7.

!eople

developprocedures

for processing

data

tep 8.

!eople use software to

enter data intocomputer (hardware)

tep 9.

oftware processesdata and directs

hardware to store and

or output information


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Dataase'a very large0 integrated

collection o& data- Models a real1world enterprise

◦ Entities 2e-g-0 teams0 games3◦ Relationships

2e-g-0 student grade and marks3

◦ More recently0 also includes activecomponents 0 o&ten called 4usiness logic5-

2e-g-0 ranking system3

A Database Management System (DBMS) is aso&tware system designed to store0 manage0and &acilitate access to dataases-


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#rom #riendster.com on/line tour


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%airl' sophisticated search aaila3le

◦

cra+ler indexes pages on the +e3◦ "e'+ord3ased search *or pages

But, currentl'

◦ data is mostl' unstructured and unt'ped

◦ search onl'4 canJt modi*' the data canJt get summaries, comple- com3inations o* data

◦ *e+ guarantees proided *or *reshness o* data,consistenc' across data items, *ault tolerance, K

◦ @e3 sites t'picall' hae a !BMS in the 3ac2ground toproide these *unctions.

The picture is changing◦ Semantic @e3 can help data modeling

◦ 5esearch groups :e.g., at Ber2ele'; are +or2ing onproiding some o* this *unctionalit' across multiple websites.


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Thought E-periment 94

◦ ou and 'our pro/ect partner are editing thesame fle.

◦ ou 3oth sae it at the same time.

◦ @hose changes surieH

=

6hought E7periment 8'

9ou:re updating a ;le-

6he power goes out-

ours ) !artners +) oth 1) 3either E) ???

A) All ) 3one +) All ince -ast ave 1) ???


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A ma/or part o* the so*t+are industr'4◦ #racle, IBM, Microso*t, S'3ase

◦ also In*ormi- :no+ IBM;, Teradata

◦ smaller pla'ers4 /aa3ased d3ms, deices, ##, K

Lots o* related industries◦ data +arehouse, document management, storage,

3ac2up, reporting, 3usiness intelligence, appintegration

#pen Source coming on strong◦ M'SNL, PostgreSNL, Ber2ele'!B

?


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Shi*t *rom computation to information

◦ al+a's true *or corporate computing◦ @e3 made this point *or personal computing

◦ more and more true *or scientifc computing

(eed *or !BMS has e-ploded in the last 'ears

◦ Corporate4 retail s+ipe)clic2streams, Ocustomer

relationship mgmt, Osuppl' chain mgmt, Odata+arehouses, etc.

◦ Scientifc4 digital li3raries, ?uman $enome pro/ect,Planet Earth, ph'sical sensors, grid ph'sics net+or2

!BMS encompasses much o* CS in a practical discipline

◦ #S, languages, theor', AI, multimedia, logic

◦ et traditional *ocus on real+orld apps

?


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>ie+s descri3e ho+users see the data.

Conceptual schemadefnes logicalstructure

Ph'sical schema

descri3es the flesand inde-es used.

!hysical chema

+onceptual chema

4iew 7 4iew 8 4iew 9

1

6sers


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Conceptual schema4

◦ Students( sid: string, name: string,login: string, age: integer, gpa:real)

◦ Courses( cid: string, cname:string,credits

:integer)◦ Enrolled( sid:string, cid:string,

grade:string) E-ternal Schema :>ie+;4

◦

Course_info( cid:string, enrollment:integer)

!hysical chema

+onceptual chema

4iew 7 4iew 8 4iew 9

1

These layers


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A t'pical !BMS has ala'ered architecture.

Each data3ases'stem has its o+n

ariations.

@uery %ptimi&ation

and Eecution

elational %perators

#iles and Access 'ethods

uffer 'anagement

1isk pace 'anagement

1

must consider

concurrency

control and

recovery


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Ecient data access !ata integrit' securit' !ata administration Concurrent access, crash recoer'

5educed application deelopment time So +h' not use them al+a'sH

◦ E-pensie)complicated to set up maintain

◦ This cost comple-it' must 3e oset 3' need

◦ $eneralpurpose, not suited *or specialpurpose tas2s :e.g.

te-t search;


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!BMS endors, programmers◦ #racle, IBM, MS, S'3ase, K

End users in man' felds

◦ Business, education, science, K !B application programmers

◦

Build enterprise applications on top o* !BMSs◦ Build +e3 serices that run o !BMSs

!ata3ase administrators :!BAs;

◦ !esign logical)ph'sical schemas

◦ ?andle securit' and authori&ation

◦ !ata aaila3ilit', crash recoer'

◦ !ata3ase tuning as needs eole


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!BMS used to maintain, Quer' large

datasets.◦ can manipulate data and e-ploit semantics

#ther 3enefts include4◦ recoer' *rom s'stem crashes,

◦ concurrent access,

◦ Quic2 application deelopment,

◦ data integrit' and securit'.


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!BAs, !B deelopers the3edroc2 o* the in*ormationeconom'

DBMS R>D represents a road0

&undamental ranch o& the scie o& computation


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Pro3lem defnition Method :ho+ to sole it;

◦ Algorithm

◦ !ata structure

◦ >erifcation *or correctness

◦ Anal'sis *or ecienc'

Coding in gien Oprogramming language Understanding o* computer Oarchitecture

OCompilation, Otesting, Ode3ugging !ocumentation


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Most dicult 5eQuires interaction 3et+een Oprogrammer

and user Specs include4

◦ Input data T'pe, accurac', units, range, *ormat, location, seQuence

◦ Special s'm3ols to signal end o* data

◦ #utput data :results; t'pe, accurac', units, range, *ormat, location, Oheadings

◦ ?o+ is output related to input

◦ An' special constraint

E-ample4 Ofnd the phone no. o* a person Pro3lems get reised o*ten


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It is the process o* planning a seQuence o*steps :called instructions; *or a computer to*ollo+.

E! 7

E! 8

E! 9

. . .


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?o+ !o @e @rite a ProgramH◦ A computer is not intelligent.

◦ A computer *rees people *rom repetitie and3oring tas2s.

Li*e C'cle Phases◦ Pro3lemSoling Phase

◦ Implementation Phase

◦ Maintenance Phase

This series o* stages is 2no+n as theO+ater*all model o* so*t+are deelopment.


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A(ALRE the pro3lem and SPECI% +hat thesolution must do.

!eelop a $E5(AL S#LUTI#( :Algorithm; to

sole the pro3lem.

>E5I% that 'our solution reall' soles thepro3lem.


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@hat Is an AlgorithmH◦ A step 3' step procedure *or soling a pro3lem in

a fnite amount o* time.

The heart o* the programming process.

?o+ do 'ou start 'our carH

A*ter 3eing satisfed +ith the algorithm, +etranslate it into a programming language.


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A set o* rules, s'm3ols, and special +ordsused to construct a computer program.


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Translating 'our algorithm into aprogramming language is called coding.

◦ (o single +a' to implement an algorithm.

@ith CGG, +e use4◦ !ocumentation 'our +ritten comments

◦ Compiler translates 'our program into machinelanguage

◦ Main Program ma' call su3algorithms


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TESTI($ 'our program means running:e-ecuting; 'our program on the computer,to see i* it produces correct results.

I* it does not, then 'ou must fnd out +hat is+rong +ith 'our program or algorithm andf- itthis is called de3ugging


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USE and M#!I% the program to meetchanging reQuirements or correct errorsthat sho+ up in using it.

Maintenance 3egins +hen 'our program isput into use and accounts *or the ma/orit'o* eort on most programs.


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Pro3lemSoling Phase◦ Anal'sis and Specifcation

◦ $eneral Solution :Algorithm;

◦ >eri*'

Implementation Phase◦ Concrete Solution :Program;

◦ Test

Maintenance Phase

◦ Use◦ Maintain


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$%A-

HI3I3$+%1E

E4IEE4IE

E4IE

1E6$

1E6$

1E6$

E

+%1E ( h o r t

c u t ?


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Is (#T porta3le

5uns onl' on a specifc t'pe o* computer

Is made up o* 3inar'coded instructions:strings o* 1s and 9s;

Is the language that can 3e directl' used 3'the computer


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A5E porta3le

User +rites a program in a language similar tonatural language

E-amples4◦ %#5T5A(

◦ A>A

◦ CGG

Most are standardi&ed 3' IS#)A(SI to proidean ocial description o* the language


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other code&rom liraries0

etc-

other code&rom liraries0

etc-

written inmachinelanguage

written inmachine

language

written in

machinelanguage

written in

machinelanguage

written in

C**

written in

C**

via compiler via lin!er

SO3RCE O)


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A seQuence is a series o* statements thate-ecute one a*ter the other

Selection :3ranch; is used to e-ecute dierent

statements depending on certain conditions.

Looping :repetition; is used to repeatstatements +hile certain conditions are met.

A su3program is used to 3rea2 the program intosmaller units.


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Statement Statement Statement & & &


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I% Condition T?E( Statement9 ELSEStatement<

Statement,

Stateme

nt

Statement%

Condition & & &

T r u e

; a l s e


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@?ILE Condition !# statement9

Statement

Condition& & &;alse

T r u e


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S3)4RO5R"M, & & &

S3)4RO5R"M,

a meaningful collection

of SE?3E8CE. SE:ECTO8. :OO4.

S3)4RO5R"M


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As2 Nuestions a3out the data, the process, theoutput, error conditions.

Loo2 *or *amiliar things certain situations arise

again and again.

Sole 3' Analog' it ma' gie 'ou a place tostart.

Use MeansEnds Anal'sis !etermine the I)#and then +or2 out the details.


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!iide and ConQuer 3rea2 up largepro3lems into managea3le units

Building Bloc2 approach sole small pieces

o* the pro3lem

Merge Solutions instead o* /oining themend to end to aoid duplicate steps.

#ercome mental 3loc2 3' re+riting thepro3lem in 'our o+n +ords.


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It is a fnite set o* instructions +hich, i**ollo+ed accomplish a particular tas2.

It is 3asicall' used to descri3e apro3lem soling method suita3le *orimplementation as a computerprogram.

Algorithm is independent o* themachine and language used *orimplementation.


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Input Rero or more Quantities are supplied

e-ternall' #utput At least one Quantit' is produced

!efniteness Each instruction is clear unam3iguous %initeness It terminates a*ter fnite steps

Eectieness Each instruction is simple to 3e carried out

manuall'.


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An Ounam3iguous specifcation o* a method Is characteri&ed 3'4

◦ #rdered seQuence o* +elldefned, eectie

operations that, +hen e-ecuted, +ill produce a resulta*ter Oterminating +ithin a fnite no o* steps


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@elldefned and eectie

(o am3iguit', a method must e-ist

$ood E-amples4

Add 9 to -

compute largest prime no. 911

compute sQuare root o* - to 6 decimalplaces

Bad e-amples4

diide 91 3' -

compute largest primecompute sQuare root o* -


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Al+a's terminate, and 3e sure a3out it Produce correct results

◦ this ma' reQuire some hard thin2ing

◦ testing helps, 3ut is not adeQuate


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Basic dierences are4◦ Program is +ritten in programming

language +hereas algorithm is in

English li2e pseudo language.◦ Program ma' 3e non terminating :#S;

+hereas algorithm should terminate infnite steps.


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Stud' o* algorithm can 3eclassifed in *our distinct areasnamel' ho+ to

◦

deise◦ e-press

◦ alidate

◦ anal'&e algorithms

Devising good algorithm4


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Devising good algorithm4◦ 5eQuires stud' o* arious design techniQues

◦ Top do+n, 3ottom up and o3/ect oriented

approaches Expressing an algorithm4

◦ $ood algorithms are e-pressed using principle o*structured programming

Validation of algorithm:◦ It should 3e alidated *or correctness o* all possi3le

legal inputs. :correct, incorrect, e-ceptions;

◦ (ote that algorithm need not 'et 3e e-pressed as a

computer program.

Analysis of an algorithm:


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Analysis of an algorithm:◦ Stud' o* 3ehaior pattern or per*ormance

profle.◦ It can 3e calculated in terms o* computing

time and space reQuirement in themachine.

6ime Comple7ity4 5unning time o* the

program as a *unction o* the si&e o* input.

Space Comple7ity4 Amount o* computermemor' reQuired during the programe-ecution.


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In topdo+n model, an oerie+ o*the s'stem is *ormulated, +ithoutgoing into detail *or an' part o* it.

Each part o* the s'stem is thenrefned in more details.

Each ne+ part ma' then 3e refnedagain, defning it in 'et more details

until the entire specifcation isdetailed enough to alidate themodel.


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This design model can also 3eapplied +hile deeloping algorithm.

It 3asicall' re*ers to successierefnement o* the pro3lem :tas2;into su3 pro3lems :su3tas2s;.

5efnement is applied until +e reach

to the stage +here the su3tas2s can3e directl' carried out.


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su"task7 su"task8 su"task9

'ain ask


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In ottom1up design indiidual partso* the s'stem are specifed in details.

The parts are then lin2ed together to

*orm larger components, +hich are inturn lin2ed until a complete s'stem is*ormed.

#3/ectoriented languages such asCGG or A>A use 3ottomup approach+here each o3/ect is identifed frst.


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It is a techniQue using +hich one can +ritealgorithms :programs; in top do+n *ashion. This techniQue should 3e used +ith eer'

leel o* refnement.

In SP, one entr' and one e-it principle isadopted in all the constructs.

Basicall' there are three structures in SP


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Se?uential 2se?uence3

entr'

T9

T<

e-it

Selection 2test3


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Selection 2test3 I* cond then task

! Cond tas29

"

I* cond then task else task#

tas2< " Cond !tas29

Repetition


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p

@hile@hile :cond; do

end+hile

!o +hile )5epeat !o

+hile :cond;


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#rdered seQuence

◦ T9, T


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◦ T9, T


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@hat is the dierence 3et+een4

7

8

9

+

7

8

9

+

>

>


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Computation o* income ta- $ien a ta- ta3le as 3elo+, compute the ta-, T, on

an income, .

?ere is an algorithm4

tep 7* Input I3+C

tep 8* +ompute ta, C

tep 9* %utput

+C-/ 0A1

) 23 +C 23*))))) )

*))))* 23 +C 23))))) ) 4 ).*)56+C7*)))))8))))* 23 +C 23"))))) *)))) 4 ).)56+C7)))))8

"))))* 23 +C ")))) 4 ).")56+C7")))))8


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tep 7* Input I3+C

tep 8a* if I3+ D 9then 9 F .9G(I3+/9)C

tep 8"* if I3+ D 8 and I3+ 9

then 7 F .8G(I3+/8)C

tep 8c* if I3+ D 7 and I3+ 8

then F .7G(I3+/7)C

tep 8d* if I3+ 7 then C

tep 9* %utput


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Ta3le loo2up4 Consider4◦ special 2e' ",

◦ length o* list, = or (, more generall'

◦ unsorted L V W:-9, '9;, :-


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?ere is refned ersion o* the algorithm4

Input C

Input (7, y7)C

Input (8, y8)C

Input (9, y9)C

Input (, y)CInput (B, yB)C

If = 7 then output (7, y7)C



If = then output (, y)CIf = B then output (B, yB)


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This algorithm does the same thing, e-ceptthat it is compact4

Input C

epeat these operations B times*

Input (, y)CIf = then output (, y)

J


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An een 3etter algorithm4

Input nC

If n D then

Input Cepeat these operations n times*

Input (, y)C

If = then output (, y)

J

J


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Use Fo+charts to isuali&e the +or2ing o* analgorithm

%or e-ample4

7

8

9

+

true

false

start

stop

#rolem @'%ind the roots o* a Quadratic eQuation o* the* Y < G 3Y G 1


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*orm aY-


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Formula'

*act V n Y n9 Y n< Y KY <Y 9

Algorithm'

input nD

i V 1D initiali$ation*act V 9D

looping

+hile :i n;

Z i V i G 9D

*act V i Y *actD

[

E7ecution

Let n V 6Di V 1D *act V 9D

%hile loop

1 6D i V i G9V9D *act V 9 Y9D

9 6D i V i G9V

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