pendalaman materi conditional dan repetition ( pengulangan )

Pendalaman Materi Conditional dan Repetition (Pengulangan)

IF THEN BersarangInput (nilai)

IF nilai > 85 AND nilai <= 100 THENOutput (‘Nilai mutu = A’)ELSEIF nilai > 60 AND nilai <= 85 THENOutput (‘Nilai mutu = B’)ELSEIF nilai > 45 AND nilai <= 60 THENOutput (‘Nilai mutu = C’)ELSEIF nilai > 30 AND nilai <= 45 THENOutput (‘Nilai mutu = D’)ELSEOutput (‘Nilai mutu = E’)

5. The value variable of nilai = 60, the result is ‘Nilai mutu = B’.6. The value variable of nilai = 101, the result is ‘Nilai mutu = E’. 7. The value variable of nilai = -5, the result is ‘Error’.

Write the algorithm to calculate cost of electricitywith following constraints :

(KWHs) Rate 0 - 500 2000501 - 1000 2000 + 0.03 * per KWH under 500 over 1001 3500 + 0.02 * per KWH under 1000

• Enter the values of previous month meters, current month meter, and then displays the total cost which would exist.

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Loops notation

1. While-Do2. Repeat-Until,and 3. For-to-Do

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WHILE-DO-ENDWHILE

• it allows a {group of} program statement(s) to be executed a number of times.

• The program statement(s) are executed when the condition evaluates as true.

• Somewhere inside the loop the value of the variable which is controlling the loop (ie, being tested in the condition) must change so that the loop can finally exit.

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The structure of the WHILE... DO... statement

... {initiation}WHILE (condition) DO

program statementprogram statement…counter statement

...• Counted loops are special types of pre-test loops. They are used when a known number of

repetitions will occur.• condition is the Boolean Expression, whether it be AND, OR, or NOT, is first carried out. If the result

is TRUE, the DO statement will then be performed. However, if the result is FALSE, the DO statement will not be executed

• Iteration will be controlled by Counter statement, wether it be increase or decrease• The value of counter will be changed at the end of loop.

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Flowchart WHILE... DO... START

END

condition = true?

action

{initiationi}

{changing counter}

yes

No

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Example 1

PseudocodeWHILE there is pressure on the mat Sound the bell

Flowchart

Pressureon mat?

Sound bell

T

F

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Example 2

PseudocodeOUTPUT('before loop starts') i 0 { Initialize counter variable }WHILE (i <= 5) DO { Loop with predicate in ()}

i i + 1 {Increment counter variable}OUTPUT('iteration number ',i)

OUTPUT('after loop ends')

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Execution • generates the output

Iteration no. i i <= 5 ? i i+1 Output

before loop starts1 0 True 1 iteration number

12 1 True 2 iteration number





67 6 False after loop ends

Here, the loop predicate is the relational test "i <= 5", which causes the loop to terminate after i is incremented to six.

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Example 3i 0 {initialize}WHILE (i < 5) DO {number of iteration}

Output (‘*’) {statement}i i + 1 {increment counter}

The result of program :*****

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Example 4• Program with enter the value of 3 student’s scores :

Pseudocode i 1WHILE i <= 3 DO

Output (‘Score student no-‘,i,’ is:’)Input (score)i i + 1

• Execution :– Score student no-1 is : __– Score student no-2 is : __– Score student no-3 is : __

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Example 5

• Average of 3 numbersnumber 0 {initialize}count 3 {counters}WHILE count > 0 DO

Input (x) {enter value of x}number number + x {sum of x variables}count count – 1 {decrement counter variable}

average number/ 3 {calculate the average}Output (average)

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REPEAT-UNTIL• Post-test loops tests the condition at the end of the loop.• The process in the loop is executed first whether it is true or false

and will keep repeating until the condition is met.• Post-test loops end when the condition is true but the loop always

do the loop at least once, even if the end condition is originally true.

• Post-test loops are also called unguarded loops because no check is made before the algorithm begins the loop structure.

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The structure of the REPEAT-UNTIL statement

... {initialize}REPEAT

program statementcounter variable

UNTIL (condition)...

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Flowchart REPEAT-UNTILMULAI

aksi

{inisialisasi}

END

condition = true?

START

Program statement {action}

{initialize}

Counter changes

No

yes

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Example 1

Pseudocode

REPEAT

Take out one item

UNTIL bag is empty Isbag

empty?

Flowchart

Take out item

T

F

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Example 2

PseudocodeOUTPUT('before loop starts') i 0 { Initialize counter variable }REPEAT

i i + 1 {Increment counter variable}OUTPUT('iteration number ',i)

UNTIL (i= 5) { termination}


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Iteration no.

i i i+1 Output i = 5 ?

before loop starts1 0 1 iteration number

1False

2 1 2 iteration number 2

False


False


False


True

6 5 6 after loop ends

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Example 3i 0 {initialize}REPEAT

Output (‘*’) {action statement}i i + 1 {increment counter}

UNTIL i=5 {end loop}The result of program :

*****

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Pseudocode i 1REPEAT

Output (‘Score student no-‘,i,’ is:’)Input (score)i i + 1

UNTIL i = 3• Execution :

– Score student no-1 is : __– Score student no-2 is : __– Score student no-3 is : __

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Example 5

• Average of 3 numbersnumber 0 {initialize}count 3 {counters}REPEAT

Input (x) {input value of x}number number + x {sum of x variables}count count – 1 {decrement counter variable}

UNTIL count=0average number/ 3 {calculate the average}Output (average)

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FOR-TO-DO• The statement inside the for block is executed a number of times

depending on the control condition. • A loop index or loop counter is an integer variable that is used to

keep track of how many times a loop has executed .• A loop limit is a variable or constant that is integer-valued, which

determines the number of times a loop will execute, or a maximum value of the loop index to be reached at loop termination. .

• A loop increment is the step size for incrementing the loop counter .

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The structure of the FOR-TO-DO statement

FOR counter variable initial_value TO final_value program statement

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Flowchart FOR-TO-DO

No

yes

START

END

Counter >= initial_value AND

counter <= final_value ?

action

{initialize}

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Example 1

Pseudocode

FOR x1 TO 5 DO

output (x)

Flowchart

x >=1 AND x <= 5 ?

START

ENDoutput (x)

No

yes

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Example 2

PseudocodeOUTPUT('before loop starts') FOR i = 1 TO 5 DO

OUTPUT('iteration number ',i)


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Iteration no.

i i >=1 AND

i<= 5 ?

Output

before loop starts1 1 True iteration number

12 2 True iteration number




56 6 False after loop ends

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Example 3

FOR i 1 TO 5 DO Output (‘*’) {action statement}

The result of program :*****

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Pseudocode

FOR i 1 TO 3 DOOutput (‘Score student no-‘,i,’ is:’)Input (score)

• Execution :– Score student no-1 is : __– Score student no-2 is : __– Score student no-3 is : __

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Example 5

• Average of 3 numbersnumber 0 {initialize}FOR i 1 TO 3 DO

Input (x) {input value of x}number number + x {sum of x variables}

average number/ 3 {calculate the average}Output (average)

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Contoh Nested Loop (pengulangan bersarang)

FOR i 0 TO 4 DOFOR j 0 TO 2 DO

Output (‘*’) {aksi}

Program output :***************

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Contoh Nested Loop (pengulangan bersarang)

• Input values of 3 student’s score that have 2 different valuesFOR i1 TO 3 DO

Output (‘Student score no-‘,i,’ are ’)FOR j1 TO 2 DO

Output (‘Score ’,j,’ :’) Input (score)

• Running : Student score no- 1 areScore, 1 : _Score, 2 : _Student score no- 2 areScore, 1 : _Score, 2 : _Student score no- 3 areScore, 1 : _Score, 2 : _

Soal 1What are values of the variable x after the execution of the followingpseudocode?

n 0 x 0While n < 15 Do If (n mod 3) = 0 Then

x x + n Output(x) n n +1

A. 1, 3, 6, 9, 12B. 0, 3, 6, 9,12C. 3, 18, 24D. 0, 3, 9,18, 30E. 3,6,9,12

Soal 2What is the output of the following pseudocode?

FOR i 1 TO 2 DOIF i mod 2 = 0 THEN FOR j 1 TO 4 DO IF j mod 2 = 1 THEN Output (‘x’) ELSE Output (‘o’)ELSE Output (i)

A. ixoxo

B. xoxoi

C. ioxox

D. oxoxi

E. ii

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Soal 3

Consider the following statement– INPUT : 7– PROCESS : 1+2+3+4+5+6+7– OUTPUT : 28

• Create your pseudocode

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Soal 4

• Determine the program of the following output,

**********

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Soal 5

• Determine the program of the following output,

**********

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Soal 6• What is the output of the following code

{Declare}X,i : IntegerAlgorithm

For X 1 to 10IF (X mod 2= 0) THEN

Output(X) i i + 1

Output(i)

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Soal 7Describe the output of the following programfor i 1 to 3 do for j 5 to 6 do Output(i,j)

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Soal 8

• Write a program that it display the traditional song “Anak Ayam”. Enter the first anak ayam from keyboard.

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Soal 9

• Write a program that display ‘*’ on even line and displays ‘#’ on odd line. Enter number of line from keyboard

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Soal 10

• Write a program which outputs triangle numbers : 1, 3, 6, 10, 15, etc.

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Soal 11 (nested loop)

• Write a program which takes two integer values from the user and outputs the multiplication tables between the first and second numbers. (eg 4 and 7 will output the 4 times table, the 5 times table, the 6 times table and the 7 times table

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Soal 12

• Write a program which validate a user password. If program accepts invalid password, the output will display “invalid password, try again!”, and then program request the password again until 3 times, after 3rd iteration, the output is ”unauthorized user” . The display to user who enter valid password is “wellcome”.

46

Soal 13

• Write a program which takes N integer values from the user and outputs the maximum.

• Illustration– N = 3• Data 1 : 15• Data 2 : 20• Data 3 : 10

– Maximum = 20

pendalaman materi conditional dan repetition ( pengulangan )

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pendalaman materi conditional