1. Developing a Program

2. Writing a program Defining the problem Planning Programming
Write down what the program will do
Planning
Write down the steps, draw a flowchart
Programming
Coding, including errors correction, testing
Documenting
Adding comments
Implementing
Improvement, making the program better

3. Objective A program can be divided into 3 parts: Input data
Processing data – Calculation, etc.
Output information/results
Calculation/
Processing
Input
Output

4. A Diagram that uses special symbols showing the steps of a program
Planning - Flowchart
A Diagram that uses special symbols showing the steps of a program

5. What is a flowchart?
A diagram made up of symbols of various shapes connected by arrows.
Those symbols indicate either actions to be taken or decisions to be made.
It may be used to describe any complicated process when a mixture of actions & decisions take place
It helps us planning & programming.

6. Flowchart Symbols T F Decision symbol
(Selection, Conditional Statement)
Terminal symbol
(Start & Stop)
Page connector
(used when run out of room at the bottom) 2
Processing symbol
(Calculate, Assign, Initialize, Declare) 1
Step connector
(go from one part to another) A
Input/Output symbol
(get, put) A

7. Terminal Symbol start stop Only one “start” & one “stop” 1 arrow only
Each flowchart starts with one “start” & ends with one “stop”
start
stop

8. Input / Output Symbol 2 arrows only Input Data Display result
1 in & 1 out
Input Data
get fullname:*
Display result
put fullname

9. Processing Symbol 2 arrows only Declaration Initialization Calculation
1 in & 1 out
Declaration
var sum : real
Initialization
sum := 30.14
Calculation

10. Decision Symbol T Q. ? F 3 arrows Question 2 out going arrows
1 in & 2 out
Question
worded this way that the answer is Yes or No
2 out going arrows
T (True, Yes)
F (False, No)
Q. ? T F

11. Loop and Block
For/while/do와 같은 반복문
여러 개의 명령어로 구성된 Block

12. Page connector 2 1 1 arrow only Shows the next page
Shows the previous page
Run out of space

13. Step connector A A 1 arrow only Appear in Use letters
Many to 1
Use letters
Go from one step to another A A

14. Arrows
From Top to Bottom & from Left to Right
Make turn
Join together

15. Example start 1.is it the door bell? 2.start 3.answer the phone
4.turn off the alarm
5.is it the telephone?
6.listen to bell ringing
7.stop
8.see who is at the door
bell ringing N N
turn off the
alarm
phone?
door? Y Y
answer the
phone
see who is
at the door
stop

16. Example const PI := 3.14 var radius, volume : real
start
Define PI
const PI := 3.14
var radius, volume : real
put “please enter...”..
get radius
volume := (4/3)*PI*radius**3
put “”
put “The volume is”, volume
Declare
radius, volume
ask radius
input radius
Calculate
volume
output
volume
stop

17. Example start 1.start declare variables 2.what is the mark
var mark: real
_____ mark
mark
stop A T F
ask mark
1.start declare variables
2.what is the mark
3.ask for mark
4.check mark>=50
5.>=50 show “U Pass”
6.<50 show “U Fail”
7.stop
get
“U Pass”
>=50
“U Fail”

18. Example with Trace Table
start x y
sum
Declare & Initialise
x & y to1 1 1 2 1 2 3 A is
sum<20
sum of x&y Y
x = y
y = sum 2 3 5 3 5 8 N A
Show x,y
and sum 5 8 13 8 13 21
stop

19. Programming Convert the steps to instructions / programming languages
Debug – correct the errors
Syntax errors
Grammar mistakes which are easily found out
Logical errors
Programs run & work but the outcome is not correct / expected
Can be found by testing

20. Documentation Add comments Use spaces wisely
Easier to understand
Use spaces wisely
Blanks, Tabs, New Lines
Easy to trace, follow & understand
Choose variables & constants names
Easy to understand, not too long or short

21. Implementation Ask others to run your program
Make it more user friendly including input & output
Make it more efficient (fewer lines)
Make it run faster
Add ending screen etc.