1. 2.0 Problem Solving PROGRAM DESIGN
Prepared by :
Pn Nurul Zakiah Binti IT Department

2. STEP 2: PROGRAM DESIGN
Definition: It is a framework or flow that shows the steps in problem solving.
Methods to design a program:
Pseudocode
Flowchart
Structure Chart
IPO Chart

3. Pseudocode
Steps in problem solving that is written half in programming code and half in human language.
For example, some part uses C language code and some part uses Malay or English language.
Advantages:
Easily understood.
Easily maintained.
The codes are changeable.
Disadvantages:
Cannot be executed in the computer.

4. Example: START Total=0, Average=0 Input a, b, c Total = a + b + c
Average = Total / 3
Output a, b, c
Output Average
END

5. Flowchart
A graphical representation of data, information and workflow using certain symbols that are connected to flow lines to describe the instructions done in problem solving.
It shows the flow of the process from the start to the end of the problem solving.

6. Enter data from keyboard Calculate total Display data and total
Flowchart
Explanation
Enter data from keyboard
Calculate total
Display data and total
START
Input
Process
Output
END

7. Explanation of basic flowchart symbol:
Simbol / Symbol
Penerangan / Explanation
Indicate the direction of data flow.
Used to connect a block to another block.
Indicates operations / process involved.
Receive / read value
Display value
Execute decision based on condition.
Test is performed and the program flow continues, based on the result.
Indicates the beginning and end of a flowchart.
Show the continuing flowchart in the same page.
Flow Lines
Process
Input / Output
Decision
Start / End Flow Lines
On-page connector Flow Lines

8. Symbol usage START True Condition True Statement False False statement
Input
Condition
False statement
Output
END
False
True Statement
True
Symbol usage

9. Cont…Explanation of basic flowchart symbol:
Output
END B
START
Input
Process
First page
Next page
Symbol Usage
Symbol
Explanation
Flowchart continues in the next page.
Off Page
Connector

10. There are few additional symbols of flowchart used in a complicated program: GOSUB and RETURN. It’s usually used in a big program.
Symbol
Explanation
Instruct the executed instruction to move to the next function
Instruct the executed instruction to return to the next instruction after the GOSUB instruction, called the function.
GOSUB
RETURN

11. area =22 / 7 * radius * radius
Output area
area
RETURN
Input radius
START
END
GOSUB area
Symbol Usage

12. Example Flowchart: Flowchart to calculate the total of fine for late returning of library books.
START
Input total_of_day
Fine = total_of_day * 0.20
Output Fine
END
Symbol Usage

13. Structure Charts
Structure chart is an additional method in preparing programs that has many sub modules.
It consists rectangular boxes, which represents all the sub modules in a program and is connected by arrows.
It illustrates the top-down design of a program and is also known as hierarchical chart because its components are in hierarchical form.
The advantage is that it is easy to be drawn and to be changed.
Format:
MainModule
SubModule 2
SubModule 3
SubModule 1
SubModule 2.1
SubModule 2.2

14. Problem: To calculate the amount of water bill
Example 1:
Problem: To calculate the amount of water
bill
Represent the modules in the program
Water bill
Get / read data
Compute the charge
Display instructions for user
Determine the late charge
Display the bill
Print the bill

15. Represent the modules in the program Display instructions for user
Example 2:
Problem: To calculate area of a circle
Represent the modules in the program
Area of a circle
Get / read data
Compute the area
Display instructions for user
Define the area
Display the area
Print the area

16. IPO Chart (Input Process Output)
Module Reference No.
Output
All inputs
All Process
Module Reference No. from structure chart
All outputs

17. Example : Calculate the Salary of Employee
Input
Process
Module Reference No.
Output
Hour
Pay rate
Start
Enter hour
Enter pay rate
Calculate salary
Display salary
End
0000
1000
2000
3000
Salary
0000