Lecture (18)Program Design

8142019 Lecture (18)Program Design

httpslidepdfcomreaderfulllecture-18program-design 115

FSB23103 1

UNIVERSITIKUALALUMPUR

MalaysiaFranceInstitute

Lecture 19Program design

Mdm Ratnawati Ibrahim



FSB23103 2



IntroductionWhen constructing a software solution a number of elements are addressed (These will become moresophisticated as knowledge and experience grows)

1 The user interface (Form1)2 The program design

(a) Class definition construction importation

(b) Module definition construction importation(c) Interface methods (Form1 code)

3 Testing(a) Identify inputs

(b) Identify outputsbull Construct test cases and form test plan



FSB23103 3



The user interfaceUsers of a program need to interact with it in some way

This might be viewed as the users conducting a dialoguewith the computerAccordingly they mightbull Read and interpret information that instructs them

how to use the systembull Issue commands to the system to indicate what they

want it to dobull Enter words and numbers into the system to provide it

with data to work withbull Read and interpret the results that are produced by

the system either on screen or as a printed report andbull Respond to and correct errorsNote that theses are secondary tasks concerned withusing the system rather than the usersrsquo primary systemobjectives



FSB23103 4



ExampleConsider the game of noughts and crosses played by twopeople (not against the computer hellipyet)

The required program is to provide a platform to play thegame by recording the lsquogoesrsquo identifying a winner andkeeping score

Accordingly we may envisage something similar to thegame played with pencil and paper

ScorePeter John



FSB23103 5



Form designRequires some knowledge of the implementation(programming language) to be aware of the facilitiesavailable

First thoughts

Questions

Finish

Score

Player 1 Player 2

3 4

Noughts Crosses

Draw

Are players to beidentified Do players take turnsto be noughts and

then crosses Who starts Start Game over ndash Crosses win



FSB23103 6

U

NIVERSITIKUALALUMPUR


Form design ndash contrsquod

Label controls and if significant indicate names

Finish

Score

Player 1 Player 2

3 4

Noughts Crosses

Draw

PictureBox picbox Labels

RadioButtonsrdbPlayer1

rdbPlayer2

TextboxestxtPlayer1ScoretxtPlayer2Score

ButtoncmdFinish

Button cmdDraw

StartLabel (Flashing)

PlayButtoncmdPlay

LabellblResult



FSB23103 7

U



AnalysisSuppose

1 The players are identified as Player 1 and Player 2 andPlayer 1 is identify before the program is run2 Player 1 - Crosses start3 Play will alternate during a game and on the start of subsequent games

4 A game can be abandoned by clicking the button

5 Picture designUse 50 pixel black and white squares

located by top left vertex


httpslidepdfcomreaderfulllecture-18program-design 815FSB23103 8

U



Class design1 Identify any class definitions to be imported

Square

2 Identify any classes to be constructed and specify theirmembers

(a) a (chequered) board

display areashow to make the board visible

(b) A lsquogorsquo ndash either a nought or a crossdisplay areavalue to indicate whether nought or cross

show to make symbol visible



U



Class definitionsbull Board



U



Class definitions ndash contrsquodbull Go



U



Form1 methodsBrainstorm what operations need to carried out and orderthembull Initialisation

Set initial values of global () variablesEg scores

Set up interface

bull Start gameInitialise variables specific to a particular gameEg record of goes number of turnsDisplay board

bull Flash promptbull Manage a lsquogorsquobull Check for a winbull Identify winner



U


M

alaysiaFranceInstitute

Form1 methods ndash contrsquodDecide how methods will be invoked click-handler call fromwithin some other method

bull Initialisation - MyBaseLoadbull Start game - cmdPlaybull Flash prompt - Timer1Tickbull Manage a lsquogorsquo - picBoxMouseDown

bull Check for a win - called from picBoxMouseDown bull Identify winner - called from picBoxMouseDown

In this way the problem is broken down into smaller subtasks Tackle each of these subtasks if necessary develop their

solution in separate projects Assemble the whole and adjust towork This might mean going back and modifying some of theconstituent components

R un



U


M


Review codeRevisit the code tobull

Eliminate redundancybull Make more readableintelligible by restructuringbreaking large methods into smaller parts considerintroducing functions

bull Check the need for global variables and where possible

make localbull Introduce comments if not already present

Perform tests to identify problems deficiencies etcEach time you complete a set of changes re-run all testcases



U


M


Example - deficiency

What happens if a player selects an occupied cell

- Need to identify and prohibit this



U


M


Deficiency ndash contrsquod

Replaced by

and

Run



FSB23103 2



IntroductionWhen constructing a software solution a number of elements are addressed (These will become moresophisticated as knowledge and experience grows)

1 The user interface (Form1)2 The program design

(a) Class definition construction importation

(b) Module definition construction importation(c) Interface methods (Form1 code)

3 Testing(a) Identify inputs

(b) Identify outputsbull Construct test cases and form test plan



FSB23103 3











FSB23103 4






ScorePeter John



FSB23103 5




First thoughts

Questions

Finish

Score

Player 1 Player 2

3 4

Noughts Crosses

Draw





FSB23103 6

U





Finish

Score

Player 1 Player 2

3 4

Noughts Crosses

Draw



rdbPlayer2


ButtoncmdFinish

Button cmdDraw


PlayButtoncmdPlay

LabellblResult



FSB23103 7

U



AnalysisSuppose







U




Square








U






U






U





Set up interface





U


M







R un



U


M









U


M







U


M



Replaced by

and

Run



FSB23103 3











FSB23103 4






ScorePeter John



FSB23103 5




First thoughts

Questions

Finish

Score

Player 1 Player 2

3 4

Noughts Crosses

Draw





FSB23103 6

U





Finish

Score

Player 1 Player 2

3 4

Noughts Crosses

Draw



rdbPlayer2


ButtoncmdFinish

Button cmdDraw


PlayButtoncmdPlay

LabellblResult



FSB23103 7

U



AnalysisSuppose







U




Square








U






U






U





Set up interface





U


M







R un



U


M









U


M







U


M



Replaced by

and

Run



FSB23103 4






ScorePeter John



FSB23103 5




First thoughts

Questions

Finish

Score

Player 1 Player 2

3 4

Noughts Crosses

Draw





FSB23103 6

U





Finish

Score

Player 1 Player 2

3 4

Noughts Crosses

Draw



rdbPlayer2


ButtoncmdFinish

Button cmdDraw


PlayButtoncmdPlay

LabellblResult



FSB23103 7

U



AnalysisSuppose







U




Square








U






U






U





Set up interface





U


M







R un



U


M









U


M







U


M



Replaced by

and

Run



FSB23103 5




First thoughts

Questions

Finish

Score

Player 1 Player 2

3 4

Noughts Crosses

Draw





FSB23103 6

U





Finish

Score

Player 1 Player 2

3 4

Noughts Crosses

Draw



rdbPlayer2


ButtoncmdFinish

Button cmdDraw


PlayButtoncmdPlay

LabellblResult



FSB23103 7

U



AnalysisSuppose







U




Square








U






U






U





Set up interface





U


M







R un



U


M









U


M







U


M



Replaced by

and

Run



FSB23103 6

U





Finish

Score

Player 1 Player 2

3 4

Noughts Crosses

Draw



rdbPlayer2


ButtoncmdFinish

Button cmdDraw


PlayButtoncmdPlay

LabellblResult



FSB23103 7

U



AnalysisSuppose







U




Square








U






U






U





Set up interface





U


M







R un



U


M









U


M







U


M



Replaced by

and

Run



FSB23103 7

U



AnalysisSuppose







U




Square








U






U






U





Set up interface





U


M







R un



U


M









U


M







U


M



Replaced by

and

Run



U




Square








U






U






U





Set up interface





U


M







R un



U


M









U


M







U


M



Replaced by

and

Run



U






U






U





Set up interface





U


M







R un



U


M









U


M







U


M



Replaced by

and

Run



U






U





Set up interface





U


M







R un



U


M









U


M







U


M



Replaced by

and

Run



U





Set up interface





U


M







R un



U


M









U


M







U


M



Replaced by

and

Run



U


M







R un



U


M









U


M







U


M



Replaced by

and

Run



U


M









U


M







U


M



Replaced by

and

Run



U


M







U


M



Replaced by

and

Run



U


M



Replaced by

and

Run

Lecture (18)Program Design

Documents

Transcript of Lecture (18)Program Design