Coding Sheets, Practice & Learning Support: Translating Between Flowcharts And Pseudocode (Copy)

Translating Between Flowcharts And Pseudocode

Purpose Of This Sheet

• Helps students convert accurately between:
  • Flowcharts → Pseudocode
  • Pseudocode → Flowcharts
• This skill is tested in:
  • Algorithm design questions
  • “Convert the following…” questions
  • Logic explanation questions
• Marks are awarded for:
  • Correct logic
  • Correct structure
  • Correct sequencing (not drawing skill)

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Core Examiner Rule (Critical)

• Flowcharts and pseudocode must represent the same logic
• Any mismatch = logic error
• Symbols and statements must map one-to-one

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Standard Flowchart Symbols And Their Meaning

Flowchart Symbol	Meaning	Pseudocode Equivalent
Oval	Start / End	START / END
Parallelogram	Input / Output	INPUT / OUTPUT
Rectangle	Process	Assignment / Calculation
Diamond	Decision	IF / WHILE condition
Flow line	Direction	Execution order

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Flowchart → Pseudocode: Basic Translation Rules

Rule 1: START / END

• Flowchart:
  • Oval labelled START / END
• Pseudocode:

START
...
END

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Rule 2: Input / Output

• Flowchart:
  • Parallelogram: “Enter number”
• Pseudocode:

INPUT number

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Rule 3: Process Box

• Flowchart:
  • Rectangle: “total = total + num”
• Pseudocode:

total ← total + num

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Rule 4: Decision Diamond

• Flowchart:
  • Diamond with Yes / No branches
• Pseudocode:

IF condition THEN
  ...
ELSE
  ...
ENDIF

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Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change AS Level Computer Science Full Scale Course

Translating Simple Sequential Flowchart → Pseudocode

Flowchart Description

• Start
• Input length and width
• Calculate area
• Output area
• End

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Correct Pseudocode

START
INPUT length
INPUT width
area ← length * width
OUTPUT area
END

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Translating Selection (IF) Flowchart → Pseudocode

Flowchart Logic

• Input mark
• If mark ≥ 50:
  • Output “Pass”
• Else:
  • Output “Fail”

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Correct Pseudocode

INPUT mark
IF mark >= 50 THEN
  OUTPUT "Pass"
ELSE
  OUTPUT "Fail"
ENDIF

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Examiner Tip

• Every decision diamond becomes:
  • One IF
  • Possibly one ELSE
• Never skip ELSE if flowchart shows two exits

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Translating Loop Flowcharts → Pseudocode

Case 1: WHILE Loop (Entry-Controlled)

Flowchart Pattern

• Decision at top
• Loop body only executes if condition TRUE

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Pseudocode Translation

WHILE condition DO
  statements
ENDWHILE

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Example Flowchart Logic

• Input x
• While x > 0:
  • Output x
  • x ← x – 1

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Correct Pseudocode

INPUT x
WHILE x > 0 DO
  OUTPUT x
  x ← x - 1
ENDWHILE

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Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change AS Level Computer Science Full Scale Course

Case 2: REPEAT UNTIL Loop (Exit-Controlled)

Flowchart Pattern

• Loop body executes first
• Condition checked at bottom

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Pseudocode Translation

REPEAT
  statements
UNTIL condition

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Example Flowchart Logic

• Input num
• Add to total
• Repeat until num = -1

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Correct Pseudocode

total ← 0

REPEAT
  INPUT num
  IF num <> -1 THEN
    total ← total + num
  ENDIF
UNTIL num = -1

OUTPUT total

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Examiner Tip

• REPEAT UNTIL condition must describe when to stop
• Do not write invalid condition here

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Translating FOR Loop Flowcharts → Pseudocode

Flowchart Pattern

• Initialisation
• Condition
• Increment step
• Loop body

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Pseudocode Translation

FOR i ← start TO end
  statements
NEXT i

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Example Flowchart Logic

• For i = 1 to 5
  • Output i

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Correct Pseudocode

FOR i ← 1 TO 5
  OUTPUT i
NEXT i

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Flowchart With Counting Logic → Pseudocode

Flowchart Logic

• Input numbers
• If number > 10:
  • Increment count
• Repeat 8 times
• Output count

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Correct Pseudocode

count ← 0

FOR i ← 1 TO 8
  INPUT num
  IF num > 10 THEN
    count ← count + 1
  ENDIF
NEXT i

OUTPUT count

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Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change AS Level Computer Science Full Scale Course

Pseudocode → Flowchart: Translation Strategy

Step-by-Step Method

1. Identify:
   • INPUT / OUTPUT
   • PROCESS
   • DECISIONS
2. Place:
   • START at top
   • END at bottom
3. Convert:
   • IF → Decision diamond
   • WHILE → Decision at top
   • REPEAT → Decision at bottom
4. Follow execution order exactly

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Translating IF–ELSE Pseudocode → Flowchart

Pseudocode

INPUT age
IF age >= 18 THEN
  OUTPUT "Allowed"
ELSE
  OUTPUT "Not Allowed"
ENDIF

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Flowchart Structure (Text Description)

• Start
• Input age
• Decision: age ≥ 18?
  • Yes → Output “Allowed”
  • No → Output “Not Allowed”
• End

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Translating WHILE Loop Pseudocode → Flowchart

Pseudocode

i ← 1
WHILE i <= 3 DO
  OUTPUT i
  i ← i + 1
ENDWHILE

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Flowchart Structure

• Start
• Set i ← 1
• Decision: i ≤ 3?
  • Yes → Output i → Increment i → Back to decision
  • No → End

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Translating REPEAT UNTIL Pseudocode → Flowchart

Pseudocode

REPEAT
  INPUT num
UNTIL num = 0

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Flowchart Structure

• Start
• Input num
• Decision at bottom: num = 0?
  • No → Loop back
  • Yes → End

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Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change AS Level Computer Science Full Scale Course

Common Translation Mistakes (High-Frequency)

Mistake 1: Reversing Condition Logic

• Writing:

UNTIL num <> 0

• When flowchart shows stop at num = 0

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Mistake 2: Missing Initialisation Box

• Variables used before being set

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Mistake 3: Extra Decision Diamonds

• Adding logic not present in pseudocode

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Mistake 4: Forgetting Loop Back Arrows

• Loop executes only once incorrectly

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Examiner-Approved Keywords (Use In Explanations)

• “The decision diamond represents the IF condition”
• “The loop continues while the condition remains true”
• “Execution flows back to the decision”
• “The exit condition is checked at the bottom”

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Flowchart ↔ Pseudocode Mapping Table (Fast Recall)

Concept	Flowchart Position	Pseudocode
IF	Middle (branch)	IF / ELSE
WHILE	Top of loop	WHILE
REPEAT	Bottom of loop	REPEAT UNTIL
Counter update	Process box	count ← count + 1
Sentinel check	Decision	UNTIL value = sentinel

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Written and Compiled By Sir Hunain Zia (AYLOTI), World Record Holder With 154 Total A Grades, 7 Distinctions and 11 World Records For Educate A Change AS Level Computer Science Full Scale Course

Exam-Ready Translation Checklist

• Does every flowchart symbol have a pseudocode equivalent?
• Are conditions written exactly (not reversed)?
• Is the loop entry/exit position correct?
• Are all inputs and outputs included?
• Does the execution order match?

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Master Translation Templates

Flowchart → Pseudocode

START
INPUT
PROCESS
IF condition THEN
  PROCESS
ELSE
  PROCESS
ENDIF
OUTPUT
END

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Pseudocode → Flowchart (Logic Order)

• START
• INPUT
• PROCESS
• DECISION
• LOOP / BRANCH
• OUTPUT
• END