Writing an algorithm as a flowchart from a problem

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Quick Questions

Shade in the A or B circle for each question.

1. A problem says: 'Ask for a password and check it is correct.' Which symbol should the check use?

A A process rectangle with one arrow out

B A decision diamond with a Yes branch and a No branch

2. Which flowchart symbol should show 'INPUT Mark'?

A Parallelogram (input/output)

B Rectangle (process)

3. Which shows a correct decision for the problem 'Is the temperature over 30?'

A Diamond containing Temp > 30, with arrows labelled Yes and No

B Diamond containing Temp > 30, with two unlabelled arrows

4. When you build a flowchart from a problem, how many Start symbols does it need?

A One Start for each decision

B One Start terminator at the top

5. A flowchart has a decision with a Yes path that reaches Stop, but the No path just ends in mid-air. What is wrong?

A The No path does not reach Stop, so the flowchart is incomplete

B Nothing, because only the Yes path needs to reach Stop

Match the Pairs

Draw a line connecting each item on the left to its match on the right.

Left column		Right column
1Diamond labelled Yes / No: Is Mark >= 50?		AA decision symbol with two labelled exits, so the flowchart can follow either path depending on the data
2Parallelogram: INPUT Mark		BYes branch: OUTPUT "Pass" → Stop; No branch: OUTPUT "Fail" → Stop
3Every path through the flowchart must reach a Stop symbol		CThe decision has only one labelled exit, so the No path is missing and the flowchart cannot finish for some data
4Check the flowchart with test data such as 50 and 49 to follow each path		DTest Mark = 50 → Yes → Pass; Test Mark = 49 → No → Fail
5Diamond with one Yes exit and no No exit		EAn input symbol that reads a value from the user into the variable Mark
6Rectangle: INPUT Mark		FInput drawn in a process rectangle instead of a parallelogram

Definitions

flowchart

Fill in the Blanks

Complete each line of code by filling in the missing parts.

Parallelogram: _____ Mark Diamond: Mark >= 50?

Diamond: Mark >= 50? ___ arrow: OUTPUT "Pass" No arrow: OUTPUT "Fail"

OUTPUT "Pass" -> ____ OUTPUT "Fail" -> Stop

Rectangle: Total _ Total + Mark

Test data: Mark = 50, expect Pass Diamond: Mark __ 50? Yes -> OUTPUT "Pass" -> Stop

Spot the Error

Shade in the letter of the line that contains an error.

Question 1

A (START)

B /INPUT Mark/

C <Mark >= 50?>

D Yes -> [OUTPUT "Pass"]

E No -> /OUTPUT "Fail"/

F (STOP)

Question 2

A (START)

B /INPUT Temp/

C <Temp > 30?>

D -> /OUTPUT "Hot"/

E No -> /OUTPUT "OK"/

F (STOP)

Question 3

A (START)

B /INPUT Price/

C [Total ← Price * Qty]

D /OUTPUT Total/

E (STOP)

Question 4

A (START)

B [Total = 0]

C /INPUT Mark/

D [Total ← Total + Mark]

E /OUTPUT Total/

F (STOP)

Question 5

A [START]

B /INPUT Num/

C [Square ← Num * Num]

D /OUTPUT Square/

E (STOP)

Answer Key

Writing an algorithm as a flowchart from a problem

Section A: Quick Questions

B — A decision diamond with a Yes branch and a No branch

A — Parallelogram (input/output)

A — Diamond containing Temp > 30, with arrows labelled Yes and No

B — One Start terminator at the top

A — The No path does not reach Stop, so the flowchart is incomplete

Section B: Match the Pairs

Diamond labelled Yes / No: Is Mark >= 50? → A decision symbol with two labelled exits, so the flowchart can follow either path depending on the data

Parallelogram: INPUT Mark → An input symbol that reads a value from the user into the variable Mark

Every path through the flowchart must reach a Stop symbol → Yes branch: OUTPUT "Pass" → Stop; No branch: OUTPUT "Fail" → Stop

Check the flowchart with test data such as 50 and 49 to follow each path → Test Mark = 50 → Yes → Pass; Test Mark = 49 → No → Fail

Diamond with one Yes exit and no No exit → The decision has only one labelled exit, so the No path is missing and the flowchart cannot finish for some data

Rectangle: INPUT Mark → Input drawn in a process rectangle instead of a parallelogram

Section C: Definitions

flowchart — A diagram that solves a problem using symbols for start, input, process, decision, output and stop, joined by arrows. Label each decision Yes or No and test every path to Stop.

Section D: Fill in the Blanks

Parallelogram: INPUT Mark
Diamond: Mark >= 50?

Diamond: Mark >= 50?
Yes arrow: OUTPUT "Pass"
No arrow: OUTPUT "Fail"

OUTPUT "Pass" -> Stop
OUTPUT "Fail" -> Stop

Rectangle: Total ← Total + Mark

Test data: Mark = 50, expect Pass
Diamond: Mark >= 50?
Yes -> OUTPUT "Pass" -> Stop

Section E: Spot the Error

D — OUTPUT must be drawn in a parallelogram (shown here as / /), not a process rectangle [ ]. It should be Yes -> /OUTPUT "Pass"/.

D — Every arrow leaving a decision must be labelled Yes or No. The line should start Yes -> so the path is clear.

B — Qty is used in the process but never input, so Total cannot be worked out. The input should be /INPUT Price, Qty/.

B — A process symbol sets a value using the assignment arrow ←, not =. It should be [Total ← 0].

A — START must be drawn in a terminator (rounded) symbol, not a process rectangle. It should be (START).