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Symbol
Notes
Process
Examples
A process within the system. The flowchart should show sufficient detail to indicate how the proposed process is to be achieved. Beware of making the process too generic.
average ← (A+B+C+D)/4
result ← A * B
Logic flow
Joins two operations.
LE
For example, if the system had to calculate an average value, a process entitled ‘Calculate Average’ would be too generic. It needs to indicate the inputs or other values used to calculate the average.
INPUT A, B
The arrowhead indicates the direction of the flow. Decision
A point in the sequence where alternative paths can be taken.
forward(100)
TRUE
Number > 10
M
P
The condition on which the flow is determined is written within the symbol. Where multiple alternatives exist, sequence flows are indicated by chained decision symbols. Each ‘FALSE’ condition directs to another decision.
result ←A * B
FALSE
FALSE
FALSE repeatIs×Input 4 =A
FALSE right(90) Is Input =B Is Input =C
OUTPUT result
TRUE
TRUE
TRUE
Table 2.3: Symbols used in a flowchart
KEY WORD
Use a flowchart to represent the process of calculating an estimated arrival time for an aeroplane journey.
condition: the criteria that are tested as part of the execution of the code. The condition will result in either a True or False answer when tested.
A
DEMO TASK 2.1
Solution
The steps in the process are:
Step 1 Obtain location of journey start and end airports.
S
Step 2 Obtain the distance between the two airports. Step 3 Calculate the time it will take to complete the journey. Step 4 Obtain the time the journey will start. Step 5 Calculate the estimated arrival time by adding the journey time to the start time. Step 6 Output the estimated arrival time.
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