1. Pseudocode
Skill Area 305.2
Materials Prepared by Dhimas Ruswanto, BMm

2. Lecture Overview Pseudocode Pseudocode (Sequence)
Pseudocode (Selection)
Pseudocode (Iteration)
Examples

3. Pseudocode
Pseudocode consists of short, English phrases used to explain specific tasks within a program’s algorithm.

4. Pseudocode
Used to provide an outline description of the specification for the software module
Contain a natural language of expressions embedded in syntactic structures taken from programming language
IF…THEN…ELSE
REPEAT..UNTIL
Not intended to be executed by a computer, must be interpreted by people.

5. Pseudocode Sequence

6. Pseudocode (Sequence)
When we write programs, we assume that the computer executes the program starting at the beginning and working its way to the end.
This is a basic assumption of all algorithm design.
We call this SEQUENCE.

7. Pseudocode (Sequence)
In pseudo-code it looks like this:
Statement1;
Statement2;
Statement3;
Statement4;
Statement5;
Statement6;
Statement7;
Statement8;

8. Pseudocode (Sequence)
For example, for making a cup of tea:
Organise everything together;
Plug in kettle;
Put teabag in cup;
Put water into kettle;
Wait for kettle to boil;
Add water to cup;
Remove teabag with spoon/fork;
Add milk and/or sugar;
Serve;

9. Pseudocode (Sequence)
Or as a program:
BEGIN
PROGRAM MakeACupOfTea:
Organise everything together;
Plug in kettle;
Put teabag in cup;
Put water into kettle;
Wait for kettle to boil;
Add water to cup;
Remove teabag with spoon/fork;
Add milk and/or sugar;
Serve;
END.

10. Pseudocode SeLECTION

11. Pseudocode (Selection)
What if we want to make a choice
example, do we want to add sugar or not to the tea?
We call this SELECTION.

12. Pseudocode (Selection)
So, we could state this as:
IF (sugar is required)
THEN add sugar;
ELSE don’t add sugar;
ENDIF;

13. Pseudocode (Selection)
Or, in general:
IF (<CONDITION>)
THEN <Statements>;
ELSE <Statements>;
ENDIF;

14. Pseudocode (Selection)
Or to check which number is biggest:
IF (A > B)
THEN Print A + “is bigger”;
ELSE Print B + “is bigger”;
ENDIF;

15. Pseudocode (Selection)
Adding a selection statement in the program:
BEGIN
PROGRAM MakeACupOfTea:
Organise everything together;
Plug in kettle;
Put teabag in cup;
Put water into kettle;
Wait for kettle to boil;
Add water to cup;
Remove teabag with spoon/fork;
Add milk;
IF (sugar is required)
THEN add sugar;
ELSE do nothing;
ENDIF;
Serve;
END.

16. Pseudocode ITERATION

17. Pseudocode (Iteration)
What if we need to tell the computer to keep doing something until some condition occurs?
Let’s say we wish to indicate that the you need to keep filling the kettle with water until it is full.
We need a LOOP, or ITERATION.

18. Pseudocode (Iteration)
WHILE (a true condition)
STATEMENT
or STATEMENT BLOCK concluded with
ENDWHILE
WHILE Loop
REPEAT
statement
UNTIL (condition is true)
REPEAT UNTIL Loop
FOR (starting state, final state, increment)
Statement
ENDFOR
FOR Loop

19. Pseudocode (Iteration)
So, we could state this as:
WHILE (Kettle is not full)
DO keep filling kettle;
ENDWHILE;
Or to print out the numbers 1 to 5:
A = 1;
WHILE(A > 5)
DO Print A;
A = A + 1;
ENDWHILE;

20. What is the benefit of using loop?
Get first entry
If this is the required entry
Then write down phone number
Else get next entry
If this is the correct entry
then write done entry
else get next entry
if this is the correct entry
Consider the problem of searching for an entry in a phone book with only condition:
Get first entry;
Call this entry N;
WHILE N is NOT the required entry
DO Get next entry;
ENDWHILE;
We may rewrite this as follows:

21. Pseudocode (Iteration)
BEGIN
PROGRAM MakeACupOfTea:
Organise everything together;
Plug in kettle;
Put teabag in cup;
WHILE (Kettle is not full)
DO keep filling kettle;
ENDWHILE;
Wait for kettle to boil;
Add water to cup;
Remove teabag with spoon/fork;
Add milk;
IF (sugar is required)
THEN add sugar;
ELSE do nothing;
ENDIF;
Serve;
END
Or as a program:

22. Pseudocode eXAMPLES

23. Examples So let’s say we want to express the following algorithm:
Read in a number and print it out.
BEGIN
PROGRAM PrintNumber:
Use variables: A OF TYPE Integer
Read A;
Print A;
END

24. Examples So let’s say we want to express the following algorithm:
Read in a number and print it out double the number
BEGIN
PROGRAM PrintDoubleNumber:
Use variables: A,B OF TYPE Integer
Read A;
B = A*2;
Print B;
END

25. Examples BEGIN PROGRAM PrintBiggerOfTwo:
So let’s say we want to express the following algorithm to print out the bigger of two numbers:
Read in two numbers, call them A and B. Is A is bigger than B, print out A, otherwise print out B.
BEGIN
PROGRAM PrintBiggerOfTwo:
Use variables: A,B OF TYPE Integer
Read A;
Read B;
IF (A>B)
THEN Print A;
ELSE Print B;
ENDIF;
END

26. Examples
So let’s say we want to express the following algorithm to print out the bigger of three numbers:
Read in three numbers, call them A, B and C.
If A is bigger than B, then if A is bigger than C, print out A, otherwise print out C.
If B is bigger than A, then if B is bigger than C, print out B, otherwise print out C.

27. Examples BEGIN PROGRAM BiggerOfThree: Read A; Read B; Read C;
Use variables: A,B,C OF TYPE Integer
Read A;
Read B;
Read C;
IF (A>B)
THEN IF (A>C)
THEN Print A;
ELSE Print C;
END IF;
ELSE IF (B>C)
THEN Print B;
END

28. Examples So let’s say we want to express the following algorithm:
Print out the numbers from 1 to 5
BEGIN
PROGRAM Print1to5:
Use variables: A OF TYPE Integer
A = 1;
WHILE (A != 6)
DO Print A;
A = A + 1;
ENDWHILE;
END

29. Examples BEGIN PROGRAM ComputeSum:
Use variables: number1, number2, sum
OF TYPE Integer
DISPLAY “Enter the numbers”
ACCEPT number1, number2
Sum:=number1 + number2
DISPLAY “SUM”
END

30. Examples BEGIN PROGRAM CategoryOfInsurance:
Use variables: category OF TYPE character
insurance OF TYPE string
ACCEPT category
DO CASE of category
CASE category = U
DISPLAY Insurance := “not available”
CASE category = A
DISPLAY Insurance := “double”
CASE category = B
DISPLAY Insurance := “normal”
CASE category = M
DISPLAY Insurance := “medically dependent”
OTHERWISE DISPLAY “entry is invalid”
ENDCASE
END

31. Examples BEGIN PROGRAM NumberRange0-100: Use variables: number
OF TYPE Integer
REPEAT
DISPLAY “Enter a number
between 0
and 100”
ACCEPT number
UNTIL number <0 or number >100
END

32. Examples
Create a flowchart for inputting your employee’s name. If the first letter starts from A to J then display “ First Category” , if K to T then display “ Second Category” otherwise display Third Category
If student's grade is greater than or equal to 60
Print "passed“ else Print "failed“
Set the counter to 0. If the counter is more than 10 then customer receives free value meal otherwise no free value meal.