Code Guide: Input, Output And Variable Assignment Programs (Copy)

Input, Output And Variable Assignment Programs

Core Rules (Must Follow In Every Program)

• INPUT reads data into a variable
• Assignment stores/calculates a value into a variable using ←
• OUTPUT displays a value/message
• A variable must be:
  • Declared (when required by the question style)
  • Assigned before being used in calculations or OUTPUT
• Use meaningful identifiers (examiner-friendly)
  • Good: totalMarks, age, discountRate
  • Weak: a, b, x (only acceptable in tiny algorithms)

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Variable Declaration (Common Data Types)

Declaration Format

• DECLARE variableName : DATA_TYPE

Common AS-Level Data Types

Data Type	Used For	Example Values
INTEGER	Whole numbers	5, -12, 100
REAL	Decimal numbers	3.5, 0.25, -1.8
STRING	Text	“Ali”, “A1B2”
CHAR	Single character	“A”, “7”
BOOLEAN	True/False	TRUE, FALSE
DATE	Date values	(depends on given format)

Example Declarations

DECLARE age : INTEGER
DECLARE price : REAL
DECLARE name : STRING
DECLARE grade : CHAR
DECLARE valid : BOOLEAN

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Variable Assignment (The ← Operator)

Basic Assignment

age ← 18
name ← "Hamza"
valid ← TRUE

Assignment Using Expressions

• Arithmetic

total ← num1 + num2
area ← length * width
average ← total / count

• Using brackets to control order

result ← (a + b) * c

Common Mistakes To Avoid

• Using a variable before assigning it
  • Wrong:
    • total ← total + num
  • Correct:
    • total ← 0
    • total ← total + num

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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

INPUT Statements (Correct Patterns)

Single Input

INPUT age

Multiple Inputs (Separate Lines)

INPUT num1
INPUT num2

Input Into Arrays (If Needed)

FOR i ← 1 TO n
  INPUT marks[i]
NEXT i

Input Validation (Only If The Task Requires It)

• Range validation using REPEAT UNTIL (cleanest)

REPEAT
  INPUT mark
UNTIL mark >= 0 AND mark <= 100

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OUTPUT Statements (Correct Patterns)

Output A Variable

OUTPUT total

Output A Message

OUTPUT "Welcome"

Output Message + Variable (Exam-Safe Ways)

• Method 1: Separate outputs (safest and always accepted)

OUTPUT "Total is:"
OUTPUT total

• Method 2: Same line style (only if your accepted pseudocode format supports it)

OUTPUT "Total is ", total

Output Multiple Values Clearly

OUTPUT "Max:"
OUTPUT max
OUTPUT "Min:"
OUTPUT min

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Building Small Programs (Input → Process → Output)

Program 1: Input A Name And Output Greeting

DECLARE name : STRING
INPUT name
OUTPUT "Hello"
OUTPUT name

Program 2: Input Two Integers And Output Their Sum

DECLARE num1 : INTEGER
DECLARE num2 : INTEGER
DECLARE sum : INTEGER

INPUT num1
INPUT num2
sum ← num1 + num2
OUTPUT sum

Program 3: Input Length And Width And Output Area

DECLARE length : REAL
DECLARE width : REAL
DECLARE area : REAL

INPUT length
INPUT width
area ← length * width
OUTPUT area

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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

Assignment Patterns Students Must Memorise

Accumulator Pattern (Running Total)

• Used for totals, sums, money, marks

total ← 0
total ← total + value

Counter Pattern (Counting Occurrences)

• Used for “how many…”

count ← 0
count ← count + 1

Swap Pattern (When Two Values Need Exchanging)

temp ← a
a ← b
b ← temp

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Operator Quick Sheet (Used In Assignments)

Arithmetic Operators

Operation	Operator	Example
Add	+	sum ← a + b
Subtract	–	diff ← a - b
Multiply	*	area ← l * w
Divide	/	avg ← total / n
MOD (remainder)	MOD	IF num MOD 2 = 0 THEN

Comparison Operators

Meaning	Operator	Example
Equal	=	IF x = 5 THEN
Not equal	<>	IF choice <> "Q" THEN
Greater	>	IF score > 70 THEN
Less	<	IF temp < 0 THEN
Greater or equal	>=	IF mark >= 50 THEN
Less or equal	<=	IF age <= 18 THEN

Boolean Operators

Meaning	Operator	Example
AND	AND	IF x >= 1 AND x <= 10 THEN
OR	OR	IF opt = 1 OR opt = 2 THEN
NOT	NOT	IF NOT valid THEN

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Common Exam Mini-Tasks (With Perfect Templates)

Task A: Input 3 Numbers And Output Their Average

DECLARE a : REAL
DECLARE b : REAL
DECLARE c : REAL
DECLARE average : REAL

INPUT a
INPUT b
INPUT c
average ← (a + b + c) / 3
OUTPUT average

Task B: Input Price And Output Price After 10% Discount

DECLARE price : REAL
DECLARE finalPrice : REAL

INPUT price
finalPrice ← price - (price * 0.10)
OUTPUT finalPrice

Task C: Input Temperature In Celsius And Output Fahrenheit

• Formula: F = (C * 9 / 5) + 32

DECLARE c : REAL
DECLARE f : REAL

INPUT c
f ← (c * 9 / 5) + 32
OUTPUT f

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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

Debug-Proofing Input/Output/Assignment Questions (Mark-Saving Checks)

Check 1: Have You Initialised What Needs Initialising?

• Accumulators must start at 0
• Counters must start at 0
• Flags must start at FALSE
• Max/Min must start from first input when required

Check 2: Does Every Variable Used In An Expression Have A Value?

• Wrong:
  • area ← length * width (but width not input)
• Correct:
  • Input all required values first

Check 3: Is OUTPUT Showing The Required Value (Not The Wrong Variable)?

• Common slip:
  • Calculating sum but outputting num1

Check 4: Are Brackets Used Where Needed?

• Wrong:
  • average ← a + b + c / 3
• Correct:
  • average ← (a + b + c) / 3

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Common Mistakes And Their Fixes

Mistake 1: Using = Like Assignment (Wrong Mental Model)

• Correct assignment is always ←
• Correct comparison in IF is =
• Example:
  • Assignment:
    • x ← 10
  • Comparison:
    • IF x = 10 THEN

Mistake 2: Missing One INPUT Line

• Fix approach
  • Write a mini checklist:
    • “How many inputs are required?”

Mistake 3: Outputting Inside A Loop By Accident

• If the question asks for final output only:
  • Output after the loop, not inside

Mistake 4: Mixing INTEGER And REAL Carelessly

• If division is involved:
  • Use REAL for average and totals when needed

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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

Quick Copy-Paste Templates (Fast Revision)

Template 1: Simple IPO Program

INPUT value
result ← PROCESS(value)
OUTPUT result

Template 2: Two Inputs → One Output

INPUT a
INPUT b
result ← a + b
OUTPUT result

Template 3: Validation Then Use

REPEAT
  INPUT value
UNTIL value >= min AND value <= max

OUTPUT value

Template 4: Output Label + Value Safely

OUTPUT "Answer:"
OUTPUT result