Cost And Management Accounting Formats (AS Level): Absorption Costing Profit Statement Format (Copy)

IF, ELSE IF And ELSE Structures Explained

Purpose Of Selection Structures

• Selection allows a program to choose between alternative paths
• Examiner checks:
  • Correct condition logic
  • Correct structure and block closure
  • Clear, traceable decision flow
• IF, ELSE IF and ELSE are used when decisions depend on conditions

Basic IF Structure (Single Decision)

Correct IF Structure

IF Age >= 18 THEN
    OUTPUT "Eligible"
ENDIF

• Condition evaluated once
• If FALSE, block is skipped
• ENDIF is mandatory

IF–ELSE Structure (Two Possible Outcomes)

Correct IF–ELSE Structure

IF Score >= 50 THEN
    OUTPUT "Pass"
ELSE
    OUTPUT "Fail"
ENDIF

• One condition
• One true path
• One false path
• Both paths clearly defined

Common IF–ELSE Mistake And Fix

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

ELSE IF Structure (Multiple Conditions)

Standard ELSE IF Pattern

IF Score >= 80 THEN
    Grade ← 'A'
ELSE IF Score >= 60 THEN
    Grade ← 'B'
ELSE IF Score >= 40 THEN
    Grade ← 'C'
ELSE
    Grade ← 'F'
ENDIF

• Conditions checked top to bottom
• First TRUE condition executes
• Remaining conditions are skipped

ELSE IF Condition Ordering (Critical)

Incorrect Ordering

IF Score >= 40 THEN
    Grade ← 'C'
ELSE IF Score >= 80 THEN
    Grade ← 'A'
ENDIF

• Score = 85 gives Grade C (wrong)

Correct Ordering

IF Score >= 80 THEN
    Grade ← 'A'
ELSE IF Score >= 40 THEN
    Grade ← 'C'
ENDIF

ELSE IF Vs Nested IF (Exam-Safe Comparison)

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

Nested IF Structures (Dependent Conditions)

Nested IF Example

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

• Second IF only evaluated if first IF is TRUE
• Useful for hierarchical logic

ELSE IF Vs Nested IF (When To Choose)

Using Boolean Conditions Clearly

IF Found = TRUE THEN
    OUTPUT "Value Found"
ELSE
    OUTPUT "Not Found"
ENDIF

• Always compare BOOLEAN explicitly
• Avoid ambiguous conditions

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

Selection With Compound Conditions

Compound Condition Example

IF (Age >= 18) AND (HasID = TRUE) THEN
    OUTPUT "Allowed"
ELSE
    OUTPUT "Denied"
ENDIF

• Brackets improve readability
• Prevents logic misinterpretation

Assignment Inside Selection (Clean Logic Pattern)

IF Score >= 50 THEN
    Result ← "Pass"
ELSE
    Result ← "Fail"
ENDIF

OUTPUT Result

• Decision and output separated
• Easier marking and tracing

IF Inside Loops (Very Common Exam Pattern)

FOR i ← 1 TO 5
    IF Marks[i] >= 50 THEN
        PassCount ← PassCount + 1
    ENDIF
ENDFOR

• IF controls action per iteration
• Loop logic remains clean

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

ELSE IF With Validation Logic

REPEAT
    INPUT Choice
    IF Choice < 1 THEN
        OUTPUT "Too low"
    ELSE IF Choice > 3 THEN
        OUTPUT "Too high"
    ENDIF
UNTIL Choice >= 1 AND Choice <= 3

• Multiple validation messages
• Controlled exit condition

Common Examiner Mistakes And Fixes

Examiner-Safe Selection Template

IF condition THEN
    statements
ELSE IF condition THEN
    statements
ELSE
    statements
ENDIF

• Clean
• Predictable
• Examiner-friendly