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Nhpmn

Cng ngh hc Phn mmIntroduction to Software Engineering

Department of Software Engineering

Faculty of Information Technology

Hanoi University of TechnologyTEL: 04-8682595 FAX: 04-8692906

Email: cnpm@it-hut.edu.vn

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.1

Phn IV

Thit k v Lp trnh

Design and Programming

Chng 6:

Phng php thit k h thng

6.1. Thit k h thng l g?

6.2. Phng php thit k h thng

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.2

6.1.Thit k h thng l g?

L thit k cu hnh phn cng v cu trcphn mm (gm c chc nng v d liu) cc h thng tha mn cc yu cu ra

C th xem nh Thit k cu trc (WHAT), chkhng phi l Thit k Logic (HOW)

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.3

Quy trnh thit k h thng

Phn chia m hnh phn tch ra cc h con

Tm ra s tng tranh (concurrency) trong hthng

Phn b cc h con cho cc b x l hoc ccnhim v (tasks)

Pht trin thit k giao din

Chn chin lc ci t qun tr d liu

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.4

Quy trnh thit k h thng (tip) Tm ra ngun ti nguyn chung v c ch iukhin truy nhp chng

Thit k c ch iu khin thch hp cho hthng, k c qun l nhim v

Xem xt cc iu kin bin c x l nh thno

Xt duyt v xem xt cc tha hip (trade-offs)

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.5

Cc im lu khi thit k h thng

(1) C th trch c lung d liu t h thng: l phn ni dung c t yu cu v giaodin

(2) Xem xt ti u ti nguyn kin trc ln hthng ri quyt nh kin trc

(3) Theo qu trnh bin i d liu, hy xemnhng chc nng c kin trc nh th no

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.6

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Cc im lu (tip)(4) T kin trc cc chc nng theo (3), hy xem xt

v chnh li, t chuyn sang kin trc chngtrnh v thit k chi tit

(5) Quyt nh cc n v chng trnh theo ccchc nng ca h phn mm c da theo lungd liu v phn chia ra cc thnh phn

(6) Khi cu trc chng trnh ln qu, phi phn chianhhn thnh cc mun

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.7

Cc im lu (tip)

(7) Xem xt d liu vo-ra v cc tp dng chungca chng trnh. Truy cp tp ti u

(8) Hy ngh xem c c nhng thit k trnth nn dng phng php lun v nhng k

thut g ?

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.8

Thit k h thng Thit k h thng

Thit k h thng phn cng [(1), (2)]

Thit k h thng phn mm [(3)-(7)]

Thit k h thng phn mm

Thit k tp (file design) [(7)]

Thit k chc nng h thng [(3)-(6)]

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.9

6.2 Phng php thit k h thng

Phng php thit k cu trc ha (StructuredDesign) ca Constantine

Ngoi ra cn cc phng php khc, nhPhng php thit k tng hp (CompositeDesign) caMyers

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.10

Thit k cu trc ha

Bt ngun t modularity, top-down design, structured programming

Cn xem nh Phng php thit k hnglung d liu (Data flow-oriented design)

Quy trnh 6 bc: (1) to kiu lung thng tin; (2) ch ra bin ca lung; (3) nh x DFD sang cu trcchng trnh; (4) xc nh phn cp iu khin; (5) tinh lc cu trc; (6) chn m t kin trc

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.11 HUT, Falt. of IT Dept. of SE, 2001 SE-IV.12

Thit k cu trc ha

(1) Mun v tham s

(2) Lu bong bng v cu trc phn cp

Lu bong bng (Bubble chart)

Cu trc phn cp (Hierarchical structured chart)

(3) Phng php phn chia STS

(Source/Transform/Sink) v TR (Transaction)

(4) Phn tch cu trc ha

(5) Chun phn chia mun

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(1) Mun

Dy cc lnh nhm thc hin chc nng(function) no

C th c bin dch c lp

Mun c dch c th c mun khcgi ti

Giao din gia cc mun thng qua cc bintham s (arguments)

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.13

(2a) Lu bong bng (Bubble chart)

Biu th lung x l d liu

K php

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.14

Tn

chc nng

Tn d liu Tn d liu

(D liu vo) (D liu ra)(Bong bng)

(2b) Cu trc phn cp(Hierarchical structured chart)

L phn cp biu th quan h ph thuc gia ccmun v giao din (interface) gia chng

Cc quy c:

Khng lin quan n trnh t gi cc mun, nhng ngmnh l t tri qua phi

Mi mun xut hin trong cu trc 1 ln, c th c ginhiu ln

Quan h trn di: khng cn nu s ln gi

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.15

Hierarchical structured chart

Cc quy c (tip): Tnmun biu th chc nng (lm g), t tn sao chocc mun pha di tng hp li s biu th chc nngcamun tng ng pha trn

Bin s (arguments) biu th giao din gia cc mun, bins cc mun gi/bgi c th khc nhau

Mi tn vi ui trn trng biu th d liu, ui trn en(hng) biu th flag

Chiu ca mi tn l hng truyn tham s

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.16

Hierarchical structured chart

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.17

Module A

Module B Module C Module D

Module E

1

Lung d liu

Lung flag

(3) Phng php phn chia STS, TR

Thit k cu trc:

Phng php phn chia STS(Source/Transform/Sink: Ngun/Bini/Hpth)

Phng php phn chia TR (Transaction)

Minh ha phn chia chc nng theo bong bngcaDFD (biu lung d liu)

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.18

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(3a) Phng php phn chia STS

1) Chia i tng bi ton thnh cc chc nngthnh phn

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.19

Bi ton

Problem

F1

F2

F3

F4F5

Quyt nh lung d liu chnh

2) Tm ra lung d liu chnh i qua cc chc nng: tu vo (Input) ti u ra (Output)

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.20

F1

F2

F3

F4

F5

INPUT

OUTPUT

Lung d

liu chnh

Quyt nh bong bng v d liu3) Theo lung d liu chnh: thay tng chc nngbi bong bng v lm r d liu gia cc bong

bng

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.21

F2 F3 F4 F5F1Data1 Data2 Data3 Data4 Data5 Data6

INPUT OUTPUT

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.22

T s bong bng sang

s phn cp

4) Xc nh v tr tru tng ha ti a u

vo v u ra

F2 F3 F4 F5F1Data1 Data2 Data3 Data4 Data5 Data6

INPUT OUTPUTTru tng hati a u vo

Tru tng hati a u ra

Source Module Transform Module Sink Module

5) Chuyn sang s phn cp

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.23

F2 F3 F4 F5F1Data1 Data2 Data3 Data4 Data5 Data6INPUT OUTPUT

Tru t-ng hati a u vo

Tru t-ng hati a u ra

Source Module Transform Module Sink Module

Control

Module

Source

Module

Transform

Module

Sink

Module

0

1 2 3

6) Xc nh cc tham s gia cc mun da theoquan h ph thuc

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.24

Module 0

Module 1 Module 2 Module 3

0

1 2 3

3

3 5 5

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7) Vi tng mun (Source, Transform, Sink) li pdng cch phn chia STS lp li cc bc t 1) n6). i khi c trng hp khng chia thnh 3 mun nh m thnh 2 hoc 1

8) Tip tc chia n mc cu trc lgic khi muntng ng vi thut ton bit th dng. Tnghp li ta c cu trc phn cp: mi nt l 1 mun vi s nhnh pha di khng nhiu hn 3

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.25

(3b) Phng php phn chia TR

Khi khng tn ti lung d liu chnh, m d liuvo c c th khc nhau nh nhng ngun khc

nhau xem nh cc Giao dch khc nhau

Mi giao dch ng vi 1 mun x l n

Phn chia mun c th: theo kinh nghim; theotnh c lp mun; theo s bc ti a trong 1 mun (v d < 50) v theo chun

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.26

(4) Phn tch cu trc ha

Xc nh lung d liu

Lung tuyn tnh th theo phn chia STS

Lung phn nhnh th theo phn chia TR

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.27

(5) Chun phn chiamun

Tnh c lp: kt hp (coupling) v bnvng (strength)

5 tiu chun caMyers Decomposability

Composability

Understandability

Continuity

Protection

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.28

c trng ca thit k cu trc ha

D thch ng vi m hnh vng i thcnc do tnh thn thin cao

Thit k theo tin trnh, khng hp vi thitk x l theo l (batch system)

Dng phn chia - kt hp gii quyt tnhphc tp ca h thng

Topdown trong phn chiamun

K thut lp trnh hiu qu

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.29

Chng 7:K thut thit k chng trnh

7.1 Thit k chng trnh l g ?

7.2 Phng php thit k chng trnh

7.3 Cng c thit k

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.30

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7.1 Thit k chng trnh l g ? L thit k chi tit cu trc bn trong ca phnmm: thit k tnh nng tng mun v giaodin tng ng

Cu trc ngoi ca phn mm: thit k hthng

Trnh t x l bn trong: Thut ton (gii thut, Algorithm); Logic

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.31

7.2 Phng php thit k chng trnh

Khng c trng thi m (fuzzy), m bothit k cu trc trong ng n

Ngn ng lp trnh ph hp

Trin khai ng n c t chc nng ccmun v chng trnh nh phng php lunthit k chi tit

Dng quy trnh thit k d chun ha tngbc

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.32

K thut thit k chng trnh

K thut thit k m hnh h phn mm

Hng tin trnh (process) : K thut thit k cutrc iu khin

Hng cu trc d liu (data): K thut thit k cutrc d liu

Hng s vt / i tng (object): K thut thit khng i tng

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.33

7.2.1 Lp trnh cu trc ha

Khi nim c bn: tun t, nhnh (chn), lp; cutrcm rng, tin x l, hu x l

Nhng im li khi thit k thut ton

Tnh c lp ca mun: ch quan tm vo-ra

Lm cho chng trnh d hiu

D theo di chng trnh thc hin

H phc tp s d hiu nh tip cn phn cp

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.34

Loi b GOTO

GOTO dng lm g?

Cho php thc hin cc bc nhy n mt nhn nht

nh

Ti sao cn loi b GOTO ?

Ph v tnh cu trc ca lp trnh cu trc ha

Phng php loi b GOTO

C th loi b GOTO trong mi trng hp?

Th no l k nng lp trnh cu trc

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.35

Lu khi thit k chng trnh

Ph thuc vo k nng v kinh nghim cangi thit k

Cn chun ha ti liu c t thit k chi tit

Khi thit k cu trc iu khin ca gii thut, v theo cc quy c cu trc ha nn i khitnh sng to ca ngi thit k b hn ch, bbuc theo khunmu c

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.36

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7.2.2 Lu cu trc ha

Tc dng ca lu (flow chart)

Quy phm (discipline)

Tru tng ha th tc

Lu cu trc ha

Cu trc iu khin c bn

Chi tit ha tng bc gii thut

Th hin c trnh t iu khin thc hin

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.37

Lu Nassi-Shneiderman(NS chart by IBM)

a- Ni (concatination) b- Chn (selection)

c- a nhnh (CASE) d- Lp (repetition)

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.38

X l 1

X l 2

Iu kinY N

X l 1 X l 2

Iu kin

X l 1

X l 2Xl 3

TT1

TT2 TT3

DO WHILE (kin)

X lREPEAT UNTIL (kin)

X l

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.39

Lu Phn tch bi ton

(PAD chart by Hitachi)

a- Ni (concatination) b- Chn (selection)

c- a nhnh (CASE) d- Lp (repetition)

WHILEkin X l

X l 1

X l 2

X l 1

X l 2

iu kin

X l1

X l2

X l3

X l4

TT1

TT2

TT3

TT4

Iu

k

in

UNTILkin X l

Trcchnh

7.2.3 V Phng phpGic-sn(Jacksonsmethod)

JSP: Jackson Structured Programming

Cc k php:

C s (elementary)

Tun t (sequence)

Lp

R nhnh

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.40

Trnh t thit k chung

Thit k cu trc d liu (Data step)

Thit k cu trc chng trnh (Program step)

Thit k th tc (Operation step)

Thit k c t chng trnh (Text step)

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.41

7.2.4 V Phng phpWa-ny(Warniers method)

Khi nim chung

Trnh t thit k Thit k d liu ra

Thit k d liu vo

Thit k cu trc chng trnh

Thit k lu

Thit k lnh th tc

Thit k c t chi tit

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.42

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Chng 8:K thut lp trnh

8.1 Lch s pht trin ca ngn ng lp trnh

8.2 Cu trc chng trnh

- Cu trc d liu d hiu

- Cu trc thut ton d hiu

8.3 Cc cng c lp trnh

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.43

8.1 Lch s ngn ng lp trnh Cc ngn ng th h th nht:

Ngn ng lp trnh m my (machine code) Ngn ng lp trnh assembly

Cc ngn ng th th th hai: FOTRAN, COBOL, ALGOL, BASIC Pht trin 1950-1970

Cc ngn ng th h th ba Ngn ng lp trnh cp cao vn nng (cu trc) Lp trnh hng i tng Lp trnh hng suy din logic

Cc ngn ng th h th t Truy vn Cc ngn ng h tr quyt nh

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.44

8.2 Cu trc d liu d hiu

Nn xc nh tt c cc cu trc d liu v ccthao tc cn thc hin trn tng cu trc d liu

Vic biu din/khai bo cc cu trc d liu chnn thc hin nhngm un s dng trctip d liu

Nn thit lp v s dng t in d liu khithit d liu

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.45

Cu trc thut ton d hiu

Algorithm

Structured coding v 9 im lu : Tun theo quy cch lp trnh

Mt u vo, mt u ra

Trnh GOTO, tr khi phi ra khi lp v dng

Dng comments hp l

Dng tn bin c ngha, gi nh

Cu trc lng r rng

Trnh dng CASE / switch nhiu hoc lng nhau

M ngun 1 chng trnh / mun nn vit trn 1 trang

Trnh vit nhiu lnh trn 1 dng

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.46

IF THEN / IF THEN ELSE

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.47

K Cng vic1

Cng vic 2

=0

0PASCAL

if iu kin then

begin

cng vic 1

end;

else

begin

cng vic 2

end

Ngn ng C

if (iu kin)

{ cng vic 1}

else

{cng vic 2}

CASE / switch

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.48

Ngn ng C

switch ()

{

case : ;[break;]

case : ; [break;]

case : ; [break;]

[default : ; [break;] ]

}

PASCAL

CASE

OF

gtr1: ;

gtr2: ;

...........

gtrN: ;

ELSE

;

END;

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FOR TO / DOWNTO

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.49

Bt u

KThc

Bin iu khin = Gi tr u

Bin iu khin > Gi tr cui

Thc hin

Bin iu khin = gi tr tip theo ca bin iu khin)

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.50

PASCAL

FOR binkhin := GTu TO GTCui DO

begin

end;

Ngn ng C

for ( [biuthc1] ; [biuthcK]; [biuthc2] )

{ ; }

c bit: c cc lnh thot break; continue;

exit

DOWHILE

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.51

Bt u

KThc

Cng vic

Biu thc LogicSai

ng

Kim tra iu kin trc khi thc hin

Li thng gp: Lp v hn

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.52

PASCAL

While BiuthcBoolean DO

begin

end;

Ngn ng C

while ()

{ ; }

REPEAT UNTIL

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.53

Bt u

Kthc

Cng vic

Biu thc LogicSai

ng C s khc nhau gia hai ngn ng?

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.54

PASCAL

Repeat

until Biu_thc_Boolean;

Ngn ng C

do {

;

} while ();

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Ch thch trong chng trnh Ti sao cn t cc ch thch trong chng trnh ?

V tr t cc ch thch trong chng trnh Thnh phn/ Module

Lp

Hm/th tc

Cc v tr c bit khc

Mt s quy nh khi t ch thch: Ngn gn

Gi nh

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.55

8.3 Cc cng c lp trnh Environments: DOS, WINDOWS, UNIX/LINUX

Editors, Compilers, Linkers, Debuggers

TURBO C, PASCAL

MSC, Visual Basic, Visual C++, ASP

UNIX/LINUX: C/C++, gcc (Gnu C Compiler)

JAVA, CGI, perl

C#, .NET

HUT, Falt. of IT Dept. of SE, 2001 SE-IV.56