SE Code Restructuring Solutions

8/14/2019 SE Code Restructuring Solutions

1/47

Date: 27.10.2007 SE_CodeRestructuring_Solutions.ppt Page: 1

Reverse Engineering

Code Restructuring

Guest Lecture

SolutionsSolutions

October 2007 3rd VersionOctober 2007 3rd Version

presented bypresented by

Dipl. Ing. Werner HoffmannDipl. Ing. Werner HoffmannEMAIL:EMAIL: [email protected]@t-online.de

See:See: Copyright Note in Note Page. Copyright Note in Note Page.

A member of IEEE and ACM

Mainframe

Please see thenotes pages for

additionalcomments.

ETHEidgenssische Technische Hochschule ZrichSwiss Federal Institute of Technology Zrich
mailto:[email protected]:[email protected]:[email protected]


2/47

Code Restructuring - Exercises Page: 2Date: 21.06.2007

Agenda - Exercises

1. Basic Methods

2. Restructuring

3. Some more complex examples


3/47


Agenda - Exercises

Basic Methods Restructuring

Some more complex examples


4/47


Exercise: Basic Methods (1)

A) Name the method(s) which are used for source code restructuring inthe following example. Additional name the resulting structural controlblocks.

F2

2 p2

FT

F11 p1

F

T

3

?

3

?

REPEAT F1 U(p1)

DoW(p2) F2Method:

Substitution

=


5/47


Exercise: Basic Methods (2-1)

B) Name the method(s) which are used for source code restructuring inthe following example. Name additional methods to get structuralcontrol blocks.

=

Method:

Interchange

Resolution

Transposition - KCombination J,K

Combination J,K

1

p1F

T

J

K

2 3

L

1

2

J

2 p1F

TK

1 p1

FT

3

J

K

4

L

1

2


6/47



B) Name the method(s) which are used for source code restructuring inthe following example. Name additional methods to get structuralcontrol blocks.

=

J,K

2 p1F

T

1 p1F

T

3

J,K

K

4

L

K

3 2 p1F

TJ,K

4

L

p1

Method:

Transposition

SubstitutionDOW(p1) {J,K}


7/47Code Restructuring - Exercises Page: 7Date: 21.06.2007


C) Name the method(s) which are used for source code restructuring inthe following example.

=

Method:

Transposition

1 H2 1 2

HH

H

H


8/47



D) Name the method(s) which are used for source code restructuring inthe following example. Name additional methods to get basic structuralcontrol blocks.

=

Method:

Combination

p1F

T

F,G,E

1 HIp1F

T

G

E

1 HI

F


9/47


10/47



E) Name the method(s) which are used for source code restructuring inthe following example.

=

Method: Interchange

B 1

A

C 2

D 3

B

C

1

D

2 3

A


11/47



F) Name the method(s) which are used for source code restructuring inthe following example.

Method: Inverse Notation

=

A

1 p

F

T

A

1

T

F

p

=A1 q

T

F

A1

F

T

q

Means: DO W(p) A

Means: REPEAT AU(q)


12/47


Agenda - Exercises

Basic Methods

Restructuring Some more complex examples


13/47


Exercise: Restructuring (1)

A) Restructure following flowchart and describe used methods/rules:

A

B1 p

T

F

AB

1 p

T

FB

A,B

1 p

T

FB

Step 1: Transposition B

Step 2: Combination A,B

Step 3: Pseudo Code BDoW(p) {A,B}


14/47



B) Restructure following flowchart and describe used methods/rules:

B1

q

T

Fp

T

F

A

2 B

1

q

T

F

p

T

F

A

2

B

B

1q

T

F

p

T

F

A

2

B


Step 2: Interchange

Step 3: Pseudo CodeIF pTHEN IF q

THEN AELSE B

ELSE B

te: Another method can be used: Resolution


15/47



C) Restructure following flowchart and describe used methods/rules:

B1

qT

F

p

T

F

A

2

B 1

qT

F

p

T

F

A

2

B

B

1 q

T

Fp

T

F

A

2

B


tep 2: Interchange Step 3: Inverse Notation

Step 4: Pseudo CodeIF p

THEN AELSE B

DoW(q) B


16/47


Exercise: Restructuring (3-1)

D) Restructure following flowchart and describe used methods/rules:

F2

p1T

F

p2

TF

F1 21

F3

F2,F1

p1

T

Fp2

TF

F1 21

F3

DoW( p1) {F2,F1}

First Solution:

Step 1: Transposition BStep 2: Interchange 1,2Step 3: Combination F2,F1

Step 4: Inverse Notation p1Step 5: Substitution inner DO_WHILESee next foil!


17/47




F2

p1T

F

p2

TF

F1 21

F3

p2

TF

F1,DoW ( p1) {F2,F1} 1

F3,DoW ( p1){F2,F1}

First Solution:

Step 6: Transposition DoWStep 7: Combination F1,

Combination F3,

Continue:

Step 8: Pseudo CodeF1DoW( p1) {F2,F1}DoW(p2) {F3, DoW( p1) {F2,F1}}


18/47




F2

p1T

F

p2

T

FF1 21

F3

F2,F1

p1

T

F

p2

TF

F1 21

F3

TF1 1 p1

F

p2

T

F2,F1

T

F3

O

B

B

3

4F

?O

F

Second Solution:

Step 1: Transposition F1Step 2: Interchange 1,2Step 3: Combination F2,F1

Step 4: Resolution and Cleanup

Step 5: Add control-functionB - means Back-switchO means go_out-switch?O means test for go_out

See next foil!


19/47




F2

p1T

F

p2

T

FF1 21

F3

F1 1 p1T

F

p2

T

F2,F1

T

F3

O

B

B

3

4F

?O

F

Second Solution: Step 6: Pseudo Code

F1REPEATIF p1

THEN IF p2THEN {F3, B}ELSE O

ELSE {F2,F1,B}U(?O)


20/47




Third Solution:

Step 6: Pseudo Code{F1,TRUE}REPEAT

POPIF p1

THEN IF p2THEN {F3, FALSE}ELSE TRUE

ELSE {F2,F1,FALSE}

U(TOP)

F1 1 p1T

F

p2

T

F2,F1

T

F3

3

4F

TOP

F

TRUE TRUE

FALSE

POP

FALSE


21/47


Agenda - Exercises

Basic Methods

Restructuring

Some more complexexamples


22/47


Exercise: Example 1 (1)

A) Specification:

A bank offers two mortgages. The first is for $55,000 at a monthlyrate 0f 0.6 percent. The second is for $26,000 at a monthly rate of0.9 percent.If the payment is $1,500 per month,

How long will it take to pay off both mortgages if themonthly payments reduce the first mortgages first?

How much will be the last payment be?

Use following Pseudo-Code as starting point for a code restructuretask.

After restructuring analyze and discuss the result.


23/47



A) Pseudo-Code:L1 = 55000 *loan 1

I1 = 0.006 *interest 1

L2 = 26000 *loan 2


Pay = 1500 *monthly payment

M = 0 *month numberNext_Month:

M = M + 1

p = Pay (L1*I1) (L2*I2)

IF p


24/47



Draw Flowchart:

p1

T

FF1 1 F2 p2 p3

F3

F4

p1 2 p4

3

F6

5

4

F7

T

F5

T

FT

F FT F


25/47



Restructure Flowchart:

Methods/Rules used: Resolution Combination Inverse Notation Rule 3: Indecomposable program figures

p1

T

F

F1,TRUE 1.1

F3

F4POP,TRUE

POP,F21.2

FALSE

TRUE,F7

TRUE

FALSE

p2 p3 p1

TRUE

TOP

POP

TOP p4

F6,POP,TRUE

TOP POP

F

T

T

F

T

F

F

T

T

FF

T

F

T

F5


26/47



Pseudo-Code: {F1,TRUE}REPEAT

{POP,TRUE}

REPEAT

{POP,F2}

IF p1

THEN {TRUE,F7}ELSE

FALSE

IF p2

THEN TRUEELSE {IF p3

THEN F3

ELSE F4

ENDIF

IF p1

THEN TRUE

ELSE FALSEENDIF}

ENDIF

ENDIF

UNTIL(TOP)

POP

IF TOP

THEN

ELSE IF p4

THEN {F6,POP,TRUE}

ELSE F5ENDIF

ENDIF

UNTIL(TOP)

POP


27/47



Pseudo-Code(Analyze/Discussion):

{L1=55000;I1=0006;L2=26000;I2=0.009;Pay=1500;M=0;TRUE}

REPEAT

{POP;TRUE}

REPEAT

{POP;M=M+1;p=Pay-(L1*I1)-(L2*I2)}

IF p


28/47



A) Pseudo-Code (after re-engineering):L1 = 55000 *loan 1


L2 = 26000 *loan 2


Pay = 1500 *monthly payment

M = 0 *month number

P = PAY (L1*I1) (L2*I2)

If p 0

M = M+1

P = PAY (L1*I1) L2*I2)

P = RedMort(L1,P)P = RedMort(L2,P)

End_While

Print No.month= m left= p

RedMort: Proc(L,P) Returns();* Reduce Mortgage

* Calculate remaining

* Mortgages and left amount.D = L P

IF D


29/47



A) An old Batch-Program: Task: Restructure thisflowchart and writeresulting Pseudo-Code.

START

Initialization_Routine

(1)

Jump to new page

Print Header Lines(2)

Read Order Record OIf EOF Y- Termination_Routine; END

(3)Read Address Record A

If key O = key A N-

If O.Count >= 0 N- Prepare Print_Line (O,A fields)If O.Price >= 0 N- Print Line

Calculate Sum (O.Count*O.Price) Clear Sum

Prepare Sum in Print_Line If Page_overflow N-

-Y-


30/47



A) An old Batch-Program(Solution):

START

Initialization_Routine

(1)

Jump to new page

Print Header Lines(2)

Read Order Record OIf EOF Y- Termination_Routine; END

(3)Read Address Record A

If key O = key A N-

If O.Count >= 0 N- Prepare Print_Line (O,A fields)If O.Price >= 0 N- Print Line

Calc. Sum (O.Count*O.Price) Clear Sum

Prepare Sum in Print_Line If Page_overflow N-

-Y-

F6

F1

F2

F3

REPEAT F4 U(p1)F4p1

p2p3

F5p4

F7


31/47



A) An old Batch-Program (Solution):

EOFF1 F2 F3

R F4U(p1)

F7

p2

T

F

p3

T

F

F5

4

3F6

p4

21

T

F

FT


32/47



A) An old Batch-Program (Solution) Spaghetti Bowl Approach:

EOFF1 F2 F3

R F4U(p1)

F7

p2

T

F

p3

T

F

F5

4

3F6

p4

21

T

F

FT


33/47




EOFF1 F2 F3

R F4U(p1)

F7

p2

T

F

p3

T

F

F5

4

3F6

p4

21

T

F

FT

Methods/Rules used: Transposition F2 Combination


34/47




EOF

F1

,F2

F2

F3

R F4U(p1)

F7

p2

T

F

p3

T

F

F5

4

3F6

p4

21

T

F

FT


35/47




EOFF1,F2,F3

F2,F3

F3

R F4U(p1)

F7

p2

T

F

p3

T

F

F5

4

3F6

p42

1

T

F

FT

Methods/Rules used: Transposition F3 Combination interchange


36/47




EOFF1,F2,F3

F2

F3

R F4U(p1)

F7

p2

T

F

p3

T

F

F5

4

3F6

p42

1

T

F

FT

Methods/Rules used: Transposition F3


37/47




EOFF1,F2,F3

F2

F3

R F4U(p1)

F7

p2

T

F

p3

T

F

F5

4

3F6

p42

1

T

F

FT


38/47




p5F1,F2,F3

F2

F3

R F4U(p1)

F7

p2

T

F

p3

T

F

F5

4

3F6

p42

1

T

F

TF

Methods/Rules used: Inverse Notation:

p5 = EOF = more data


39/47




p5F1,F2,F3

F2

F3

R F4U(p1)

F7

p2

T

F

p3

T

F

F5

4

3F6

p42

1

T

F

TF

p5 = EOF = more data


40/47




F1

F2

F3

DoWHILE (more_data)

REPEAT

F4

UNITL(p1)

IF p2

THEN

IF p3

THEN F5

(ELSE)

ENDIF

(ELSE)

ENDIF

F6IF p4

THEN F2

(ELSE)ENDIF

F3

EndWHILE

F7

START

Initialization-Routine

Jump to new Page

Print Header Lines

Read Order Record ODoWHILE (more_data)

REPEAT

Read Address record A

UNITL(key O = key A)IF O.Count >= 0

THEN

IF O.Price >= 0

THEN

Calc. Sum (O.Count*O.Price)

Prepare Sum into Print-line

ENDIFENDIF

Prepare Print-Line (O,A fields)

Print Line

Clear Sum

IF Page Overflow

THEN

Jump to new page

Print Header Lines

ENDIF

Read Order Record O

EndWHILE

Termination Routine

END

ProcessOrderFile

ProcessoneOrderRecord


41/47



College Admission Program:Task: Restructure thisflowchart and writeresulting Pseudo-Code.


42/47



College Admission Program(Solution):


43/47



A) A typical commercial program:

Task: Restructure thisflowchart and writeresulting Pseudo-Code.

Describe used methods/rules!


44/47



A) A typical commercialprogram (solution):

w


45/47

Date: 27.10.2007 SE_CodeRestructuring_Solutions.ppt Page: 45

Questions / CommentsQuestions / Comments

??????Questions, comments, further

information?

Please feel free to e-mail me!Dipl.Ing. Werner HoffmannDipl.Ing. Werner Hoffmann

EMAIL:EMAIL: [email protected]@t-online.deoror

[email protected]@aol.com
mailto:[email protected]:[email protected]:[email protected]


46/47


Do not


47/47

The End

Code Restructuring

Ithankyouforyourattention!

SE Code Restructuring Solutions

Documents

Transcript of SE Code Restructuring Solutions