Pseudocode Foundations & Conventions: Indentation And Structure In Pseudocode (Copy)

Indentation And Structure In Pseudocode

Why Indentation And Structure Matter In Exams

• Indentation visually represents logical hierarchy
• Examiner uses indentation to:
  • Identify blocks
  • Match IF with ENDIF
  • Trace loops accurately
• Poor indentation can make correct logic look incorrect

Core Indentation Rules (Non-Negotiable)

Basic Structured Layout (Skeleton Pattern)

DECLARE variables
Initialise variables

INPUT values

IF condition THEN
    statements
ENDIF

OUTPUT results

• Straight vertical flow
• No sideways logic
• Easy to follow under time pressure

Indentation In IF Structures

Incorrect (logic becomes unclear)

IF Age >= 18 THEN
OUTPUT "Allowed"
ELSE
OUTPUT "Denied"
ENDIF

Correct (examiner-friendly)

IF Age >= 18 THEN
    OUTPUT "Allowed"
ELSE
    OUTPUT "Denied"
ENDIF

• Indentation shows:
  • Which statements belong to IF
  • Which belong to ELSE

Nested IF Indentation (Critical Skill)

IF Age >= 18 THEN
    IF HasID = TRUE THEN
        OUTPUT "Entry Allowed"
    ELSE
        OUTPUT "ID Required"
    ENDIF
ELSE
    OUTPUT "Underage"
ENDIF

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

Indentation In CASE Structures

Correct CASE Structure

CASE Option OF
    1 : OUTPUT "Add"
    2 : OUTPUT "Delete"
    3 : OUTPUT "Search"
    OTHERWISE : OUTPUT "Invalid"
ENDCASE

• Each option clearly separated
• No ambiguity about scope

Indentation In FOR Loops

Correct Structure

FOR i ← 1 TO 5
    INPUT Value
    Total ← Total + Value
ENDFOR

Nested Loops (2D Structures)

FOR row ← 1 TO 3
    FOR col ← 1 TO 4
        OUTPUT Grid[row, col]
    ENDFOR
ENDFOR

• Each loop adds one indent level
• END statements close in reverse order

Indentation In WHILE Loops

WHILE Count < 3 DO
    INPUT Value
    Count ← Count + 1
ENDWHILE

• Everything controlled by WHILE is indented
• Condition clearly separated from body

Indentation In REPEAT UNTIL Loops

REPEAT
    INPUT Age
UNTIL Age >= 0 AND Age <= 120

• UNTIL aligns with REPEAT
• Condition is visually distinct

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

Procedures And Functions: Structural Discipline

PROCEDURE Structure

PROCEDURE DisplayResult(Mark : INTEGER)
    IF Mark >= 50 THEN
        OUTPUT "Pass"
    ELSE
        OUTPUT "Fail"
    ENDIF
ENDPROCEDURE

FUNCTION Structure

FUNCTION GetAverage(Total : INTEGER, Count : INTEGER) RETURNS REAL
    RETURN Total / Count
ENDFUNCTION

• RETURN must be indented inside function
• ENDFUNCTION aligned with FUNCTION

Indentation In Array Processing

FOR i ← 1 TO 10
    Total ← Total + Marks[i]
ENDFOR

• Array access inside loop body
• Index clearly associated with loop

Indentation In Linear Search (Exam-Standard)

Found ← FALSE
i ← 1

WHILE i <= N AND Found = FALSE DO
    IF Data[i] = Target THEN
        Found ← TRUE
    ELSE
        i ← i + 1
    ENDIF
ENDWHILE

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

Structural Alignment Of END Keywords

• END keyword must align vertically with its starter
• Misalignment suggests missing or incorrect block

Common Indentation Errors And Fixes

Examiner-Friendly Visual Checklist

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