14 programming methodology

8/17/2019 14 Programming Methodology

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WEL COME

PRAVEEN M JIGAJINNI

PGT (Computer Science)

MCA, MSc[IT], MTech[IT],MPhil (CompSci), PG!CA, A!CA,

!c Sc " En##


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Reference Book

CLASS XIBy

Sumita Arora


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C$A TER %%

R&GRAMMING

MET$&!&'&G(


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INTR&!)CTI&N

• Computerized information systems are

developed to provide computer

solutions to user problems.• The software should be designed

effectively so as to meet its objectives

of user satisfactions.


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INTR&!)CTI&N

The Software designing involves

mainly two things

1. Program Structure.

. Program !epresentation.


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PR&GRAM STRCTRE

• The program structure is decided using

top"down structure or any other popular

approach.• The main tas# is divided in to clear

logical sub tas#s there by deciding

about the sub routine and globalvariables information hiding etc.


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PR&GRAM REPRESENTATI&N

The program representation refers to its

presentation style so that the program

becomes readable and presentable.

A program which is easily understood can be

checked for errors if any, and easily modified.

It is learnt that normally 60-7! of time and"0! cost of the program is spent on testing,

debugging and modifying it.


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ST'ISTIC GI!E'INES

• $eveloping good program is s#ill and

writing good program is a %uality habit.


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ST'ISTIC GI!E'INES

• $eveloping good program is s#ill and

writing good program is a %uality habit.


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#eaningful $ames for

Identifiers &ssign 'eaningful names for identifiers

viz. variables( constants( functions etc)

$o not use similar loo#ing names li#eviz. manager( manage

&lways assign names to scalar

constants when it helps in clarity andreadability.


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%nsure clarity of %&pressions

*+pressions carry out the specified action ,s-.

Thus the must be clearly understood by the users.

Clarity of e+pressions should not be

compromised. &void programming tric#s whose intent

ill not be obvious to reader./ever sacrifice Clarity of e+pressions

even if changed e+pressions may get

minor gain in machine time.


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*e Comment* +n

Inent+tionComments play a very important

role as

they provide internaldocumentation of a program.

Always insert prologues that

comment in the beginning of aprogram.


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In*ert -l+n. 'ine* +n

Sp+ce* The insertion of blank lines and

spaces enhances the program

readability. they are to separatedeclaration blocks and comments.

Inserted before label, const.

variable declarations.


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Prett/ printin#

When program formatting is doneto make program more

readable, it is called prettyprinting.


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Ch+r+cteri*tic* &0 Goo

Pro#r+mEcient and e!ective

"ser friendly

#elf – documenting Code

$eliable

%ortable


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St+#e* &0 Pro#r+m

!e1elopment

Crack the problemCode the algorithm

Compile the program

E&ecute the program


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Ro2u*tne**

The ability of a program( to recover

following an error and to continue

operating within its environment is calledrobustness.


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Gu+r, co,e

The code which can handle e+ceptional

data errors and operational errors is

called guard code.


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T/pe* o0 Error

1.Compile"Time *rror

Synta+ error

0ccurs when rules of programming are misused

i.e when grammatical rule of c are violated.

Synta+ refers to formal rules governing the

construction of valid statements in a language.Semantics errors occur when statements are

not meaningful.


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Run3time Error*

*rror that occur during the e+ecution of

a program are run time errors. These

are harder to detect errors. Some runtime errors stop the e+ecution of the

program which is then called program

2crashed3 or 2abnormally3 terminated.


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'o#ic+l Error*

Sometimes even if you don4t encounter

any error during your compile time and

run time ( your program does notprovide the correct result. This is

because of programmer4s mista#en in

analysis of program she or he is tryingto solve. such errors are called logical

errors.


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ro2lem *ol1in#

metho,olo#/ +n, techni4ue*

5nderstanding the problem well. &nalyse the problem.

$esign the problem by

$eciding the step by step solution.

6rea#ing down solution into

smaller steps.

Code the program.

Test and debug your program.Complete your documentation.


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Te*tin# +n !e2u##in#

Testing is the process of 'ndingerrors in a program, and

debugging is the process ofcorrecting errors found duringtesting process.


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!ocument+tion

$ocumentation refers to written

descriptions specification (design (code

and comment ( internal and e+ternal toa program more understandable (

readable and more easily modifiable.


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Moule* o0 !ocument+tion

'odules ma#es information more easilyaccessible to the specific user for which they

were prepared ( and reduce the cost of

production and maintenance.

The documentation modules are generally

referred to as manuals .

7n detail it depends upon

1.Comple+ity of system.Technical sophistication of user

8.People involved in development and use


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'i*t o0 M+nu+l*

5ser manual

7nput Preparation 'anual

0peration 'anual

*%uipment 'anual

Programmer 'anual

System 'anual

Standards 'anual


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*er ocument+tion in0o

9eneral descriptions

!un flow and description

:ogic flow

Program testing;s


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Pro#r+mmer5* ocument+tion

The programmer4s 'anual provides the

technical part of documentation. This

manual is essential because it is the basis

of maintenance.

7t is of two types(

1.*+ternal documentation..7nternal documentation.


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6h+t i* e7tern+l

ocument+tion8

The e+ternal documentation of a

program consists of the writteninformation that is outside the body of

the source code.

7t may contain specifications of thehistory of the program4s development

and subse%uent modification.


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6h+t i* intern+l

ocument+tion8The internal documentation includes

comments ( self documenting code and

program4s formatting . The goal of thisfeatures to ma#e program

readable(

understandable ( and easily modifiable.


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6h+t i* *el0

ocumentin# coe8

7t is a code that uses meaningful namesfor constants( variables = subprogram

7dentifiers to clarify their meaning in theprogram.


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Pro#r+m m+inten+nce

%rogram maintenance refers to themodi'cation of a program , after it hasbeen completed . There are four kind ofmaintenance.

Corrective maintenance

#ome errors might show up because ofsome une&pected situations , untested

areas these errors are called Correctivemaintenance.


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&daptive maintenance

To accommodate changing needs (

time to time ( maintenance is done andis called adaptive maintenance.


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%reventive maintenance

If possible errors could be anticipated ,

before they actually occur, themaintenance could be done to avoidthem and the system down time( timefor which system remains out of order)

can be saved. This type of maintenanceaims at preventing errors is calledprogram maintenance.

Pro#r+m m+inten+nce


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*.The systems should be planned withan eye on the future.

+."ser speci'cation should be correct.

.The system should be modular

-.ocumentation should be complete./.#tandereds should be followed.

0.Testing should be through.

$o9 to e1elop

in0orm+tion th+t +re e+*/

to m+int+in8


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1.Ade2ate time should be allowed fordevelopment cycle.

3.Attetionshould be paid to end4users ,health and human factors should beconsidered.

5.The development team should be fullyaware at the relationship of systemdesign and system maintenance.

$o9 to e1elop

in0orm+tion th+t +re

e+*/ to m+int+in8


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T$AN:&

14 programming methodology

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