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System Flow Charts A modeling method that analy sts may use to

provide a graphic overview of the relationships between input, processing, and outputs for the whole system.Inventory

file

InventoryMasterupdate

Inventorytransaction

Inventoryupdatereport

Inventoryprocessing

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Function Decomposition Modeling Method

A function decomposition provides a conceptual overview of all the activities an organization performs in support of its overall purpose.

Business function

Manufacture product

Distribute product

Market product

Maintain operations

R & D

Market analysis

Advertising

R & D

Maintain parts

Production operations

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Procedure ModelingMethods

The modeling methods, such as HIPO diagrams,- Nassi Schneiderman charts, p rogram flow charts,

psuedocode and structured En glish, action diagrams, and structure charts, are used to h elp model the information

system procedures that event ually become instructions that make up program logic.

Program logic

Refers to the way programs ex ecute, sometimescal l ed a program’s procedur e model.

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HIPO Diagram ModelingMethod HIPO diagrams are used to hier archically show the

inputs, processing, and output s of each processing module. A HIPO diagram usually consist s of three separate

and interrelated sets of diagra ms : 1 . A visual table of contents ( VTOC) di agr am

2 . An Overview diagram 3. One or more detail diagrams

HIPO VTOC Diagrams Identifies the major procedures performed by the

system and the subordinate prooooooo ooooooooo oosuccessfully complete the maj or procedure.

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NEWEMPLOYEEHIRING 1.0

EMPLOYEEAPPLICATIONPROCESSING 1.2

NEWEMPLOYEEDATA ENTRY 1.1

DEPARTMENTPERSONNELREPORTING 1.3

PROCESSMATCHEDREQUEST 1.22

CHECK &MATCHQUALIFICATION 1.21

Figure : VTOC for processing a payroll application

System

Procedure

Subordinate Procedure

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HIPO Overview Diagrams A HIPO diagram to depict eachooooo oo oooooooooo ooo ooo oo o ooo oo oooooo, ew diagram sometimes

cr eat ed f or each module in th eVTOC.

HIPO Detail Diagrams A HIPO diagram that contains t he specific steps

i nvol ved in procedures identifi ed in the overview diagram.

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- Nassi Schneiderman Charts A procedure modeling method in which each type of

control structure is used to spe cify the set of proceduresoooooooo for a particular applic ation using the three basic

principles of good programmin oooooooooo ooo: , ,.

Sequence Selection IterationInstruction aInstruction n

• • IF

TRUE FALSEInstruction a Instruction b

LOOP STATEMENT

BODY OFLOOP

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OPEN FILEDO WHILE THERE ARE RECORD TO BE ENTEREDINPUT RECORD

FROM TERMINALVALIDATE RECORDVALID

RECORD ?YES

NOWRITE TO FILE

WRITE TOERROR FILE

CLOSE FILES

Example of Nassi-Schneiderman chart

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Program Flow Charts A procedure diagram that use s graphical symbols

oo specify the logic of progra mming procedures thatexpress sequence, selection, oooooooooo. STA

RT

A , B

A >= B

A

STOP

B

Yes

No

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Pseudocode Consists of instructions writte -n in broken English

statements that are fundame ntally equivalent to their counterparts in a particular co mputer language.

Open the filesRead a COMMISSION recordDo until end of file

Compute commissionPrint a detail lineRead a COMMISSION record

ENDDOClose the filesEnd of program

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Structured English A procedure modeling metho d si mi l ar i n use t o

pseudocode, but less cryptic i n its statement.

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Structure Charts A structure chart (STC) is a graphical modeling

method that depicts the proce dure logic of programs in a basi c f or mat consistent with the layout of structured

programs.

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Basic symbols for structure charts

14Structure chart example

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PrintAwardList

PrintSpecialLetter

CalculateCommission

ReadCommissionRecord

ProcessCommission

ReadCommissionRecord

ProcessCommissions

Structure chart

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Conversion from DFD to Structure charts

1ReadGradeRecord

2ReadCourseRecord

3ReadStudentRecord

5PrintStudentReport

4CalculateGPA.

Course Master

Grade file

Student Master

Course Record

Grade Record

StudentRecord

Course Number

StudentNumber

Course Grade

Course NumberOf Credits

GPA.

Course Description

Student

StudentReportCard

DFD Level 0

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5.1FormatStudentName and

Address line

5.2FormatCourseGrade line

5.4Write

ReportCard line

5.3FormatGrade PointAverage

line

Course Description

Course Grade

Grade PointAverage

Grade PointAverage Line

StudentReportCard

Student Nameand Address

CourseGrade Line

Child diagram

Name andAddress Line

18A structure chart for producing student report cards

ReadGradeRecord

ReadCourseRecord

ReadStudentRecord

CalculateGrade Point

Average

Print StudentReport Card

Format StudentName andAddress Line

ProduceStudentReport Card

PrepareStudentReport Card

Format CourseGrade Line

Format Grade PointAverage Line

WriteReportCard Line

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