Reference

Pseudocode ↔ Python

Every construct from the Cambridge pseudocode guide, with the Python you'd write in Paper 4. Filter for your syllabus and bookmark this. Try any snippet in the Playground → — complete Python programs have a Run Python button that opens them in the Python Playground.

Source: Cambridge 9618 Pseudocode Guide for Teachers — For examination in 2027, 2028 and 2029

Pseudocode string manipulation functions will always be provided in examinations (§5.5). Any pseudocode functions used in an examination will be defined (§8).

Changes this year: 9618 guide 2026 → 2027–29: no changes to syntax or functions. Only fix: the Cat class example in §10.2 now declares Breed : STRING (was INTEGER). The 9618 2027–29 syllabus update (version 2, Dec 2025) only clarifies papers and calculators — nothing in pseudocode.

The guide's constructs and examples are transcribed from Cambridge's guide, © Cambridge University Press & Assessment; the Python versions and notes are ZAK's.

Official PDF (2027–29) ↗2026 edition ↗

40 constructs. Badges mark the ones that belong to one syllabus only.

§1 How pseudocode appears in the exam §1.1–1.5

Monospaced font, three-space indentation, keywords in UPPER CASE, identifiers in MixedCase, meta-variables in <angle brackets>. Comments start with // and run to the end of the line.

Comments (§1.5) — the guide's own example

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CAIE pseudocode// this procedure swaps
// values of X and Y
PROCEDURE SWAP(BYREF X : INTEGER, Y : INTEGER)
   DECLARE Temp : INTEGER
   Temp ← X   // temporarily store X
   X ← Y
   Y ← Temp
ENDPROCEDURE

Python# this procedure swaps
# values of x and y
def swap(x, y):
    return y, x

💡 Note the guide: when several parameters use the same method, BYREF need not be repeated — here Y is also BYREF. The guide leaves Temp undeclared; the Playground (like an examiner) expects the DECLARE.

Meta-variables (§1.3)

Run Python

CAIE pseudocodeREPEAT
   <statement(s)>
UNTIL <condition>

Python# <…> means “substitute something here”

💡 Angle brackets are never typed in real code — they show where your own statements/conditions go.

§2 Variables, constants & data types §2.1–2.6

Six basic types: INTEGER, REAL, CHAR, STRING, BOOLEAN, DATE. Declare before use. Identifiers: letters, digits, underscore; start with a letter; case-insensitive. Assignment is ←.

Literals (§2.2)

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CAIE pseudocodeDECLARE Count : INTEGER      // 5, -3
DECLARE Price : REAL         // 4.7, 0.3, -4.0 (a digit each side of the point)
DECLARE Grade : CHAR         // 'x', 'C', '@'  (single quotes)
DECLARE Name : STRING        // "This is a string", ""  (double quotes)
DECLARE Found : BOOLEAN      // TRUE, FALSE
DECLARE DOB : DATE           // 02/01/2005 (dd/mm/yyyy)
Count ← -3
Price ← 4.7
Grade ← 'C'
Name ← ""
Found ← TRUE
DOB ← 02/01/2005
OUTPUT Count, " ", Price, " ", Grade, " ", Found, " ", DOB

Pythoncount = -3
price = 4.7
grade = 'C'
name = ""
found = True
from datetime import date
dob = date(2005, 1, 2)

💡 DATE is a 9618 type only — 2210 has just INTEGER, REAL, CHAR, STRING and BOOLEAN.

Variable declarations (§2.4)

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CAIE pseudocodeDECLARE Counter : INTEGER
DECLARE TotalToPay : REAL
DECLARE GameOver : BOOLEAN

Pythoncounter: int = 0
total_to_pay: float = 0.0
game_over: bool = False

💡 Format: DECLARE <identifier> : <data type>. In 9618 you are expected to declare every variable.

Constants (§2.5)

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CAIE pseudocodeCONSTANT HourlyRate = 6.50
CONSTANT DefaultText = "N/A"
OUTPUT HourlyRate * 40, " ", DefaultText

PythonHOURLY_RATE = 6.50
DEFAULT_TEXT = "N/A"

💡 Only a literal may be the value of a constant — never a variable, another constant or an expression. (The Playground enforces this.)

Assignment (§2.6)

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CAIE pseudocodeDECLARE Counter, NumberOfHours : INTEGER
DECLARE TotalToPay : REAL
CONSTANT HourlyRate = 6.50
Counter ← 0
Counter ← Counter + 1
NumberOfHours ← 12
TotalToPay ← NumberOfHours * HourlyRate
OUTPUT Counter, " ", TotalToPay

Pythoncounter = 0
counter = counter + 1
total_to_pay = number_of_hours * HOURLY_RATE

💡 The operator is ← (you may write <- in exams). A single = is comparison, not assignment.

§3 Arrays §3.1–3.2

Fixed-length, one data type, consecutive indices. State the lower bound explicitly — usually 1. Two-dimensional arrays use two ranges.

Declaring arrays (§3.1)

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CAIE pseudocodeDECLARE StudentNames : ARRAY[1:30] OF STRING
DECLARE NoughtsAndCrosses : ARRAY[1:3,1:3] OF CHAR

Pythonstudent_names = [""] * 30
noughts_and_crosses = [[' '] * 3 for _ in range(3)]

💡 Python lists start at 0, so StudentNames[1] ↔ student_names[0].

Accessing elements (§3.2)

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CAIE pseudocodeDECLARE StudentNames : ARRAY[1:30] OF STRING
DECLARE NoughtsAndCrosses : ARRAY[1:3,1:3] OF CHAR
DECLARE n : INTEGER
n ← 1
StudentNames[1] ← "Ali"
NoughtsAndCrosses[2,3] ← 'X'
StudentNames[n+1] ← StudentNames[n]
OUTPUT StudentNames[2], " ", NoughtsAndCrosses[2,3]

Pythonstudent_names[0] = "Ali"
noughts_and_crosses[1][2] = 'X'
student_names[n] = student_names[n - 1]

Whole-array assignment & filling with a loop (§3.2)

9618 only Run Run Python VB.NET · Java

CAIE pseudocodeDECLARE StudentNames : ARRAY[1:30] OF STRING
DECLARE Backup : ARRAY[1:30] OF STRING
DECLARE Index : INTEGER
FOR Index ← 1 TO 30
   StudentNames[Index] ← ""
NEXT Index
StudentNames[7] ← "Sara"
Backup ← StudentNames      // allowed: same size and type
OUTPUT Backup[7]

Pythonstudent_names = [""] * 30
backup = student_names.copy()

💡 Do NOT write StudentNames[1 TO 30] ← "" — the guide says to use a loop instead.

§4 User-defined data types §4.1–4.2

Non-composite: enumerated and pointer. Composite: record, set, class/object (§10). ADTs (stack, queue, linked list, dictionary, binary tree) are built from these.

Enumerated type (§4.1)

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CAIE pseudocodeTYPE Season = (Spring, Summer, Autumn, Winter)
DECLARE ThisSeason, NextSeason : Season
ThisSeason ← Spring
NextSeason ← ThisSeason + 1
OUTPUT NextSeason

Pythonfrom enum import Enum
class Season(Enum):
    SPRING = 1; SUMMER = 2; AUTUMN = 3; WINTER = 4
this_season = Season.SPRING
next_season = Season(this_season.value + 1)

💡 Values have an order, so + 1 moves to the next value and < > comparisons work.

Pointer type (§4.1) — ^ declares, ^Var takes the address, Ptr^ dereferences

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CAIE pseudocodeTYPE TIntPointer = ^INTEGER
DECLARE MyPointer : TIntPointer
DECLARE Count : INTEGER
Count ← 5
MyPointer ← ^Count        // address of Count
MyPointer^ ← MyPointer^ + 1   // access the value stored at the memory address
OUTPUT Count

Python# Python has no raw pointers; the closest idea is
# two names bound to one mutable object.
count = [5]
my_pointer = count
my_pointer[0] += 1
print(count[0])

💡 Declaring the pointer VARIABLE does not use ^ — only the TYPE definition, the address-of and the dereference do.

Record type (§4.1)

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CAIE pseudocodeTYPE StudentRecord
   DECLARE LastName : STRING
   DECLARE FirstName : STRING
   DECLARE DateOfBirth : DATE
   DECLARE YearGroup : INTEGER
   DECLARE FormGroup : CHAR
ENDTYPE
DECLARE Pupil1, Pupil2 : StudentRecord
Pupil1.LastName ← "Johnson"
Pupil1.FirstName ← "Leroy"
Pupil1.DateOfBirth ← 02/01/2005
Pupil1.YearGroup ← 6
Pupil1.FormGroup ← 'A'
Pupil2 ← Pupil1
OUTPUT Pupil2.FirstName, " ", Pupil2.LastName

Pythonfrom dataclasses import dataclass
from datetime import date
@dataclass
class StudentRecord:
    last_name: str = ""
    first_name: str = ""
    date_of_birth: date = date(2000, 1, 1)
    year_group: int = 0
    form_group: str = ""
pupil1 = StudentRecord("Johnson", "Leroy", date(2005, 1, 2), 6, 'A')
import copy; pupil2 = copy.copy(pupil1)

Array of records (§4.2)

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CAIE pseudocodeTYPE StudentRecord
   DECLARE LastName : STRING
   DECLARE YearGroup : INTEGER
ENDTYPE
DECLARE Form : ARRAY[1:30] OF StudentRecord
DECLARE Index : INTEGER
FOR Index ← 1 TO 30        // every field must be given a value before it is read
   Form[Index].YearGroup ← 7
NEXT Index
FOR Index ← 1 TO 30
   Form[Index].YearGroup ← Form[Index].YearGroup + 1
NEXT Index
OUTPUT Form[30].YearGroup

Pythonform = [StudentRecord() for _ in range(30)]
for s in form:
    s.year_group += 1

Set type (§4.1)

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CAIE pseudocodeTYPE LetterSet = SET OF CHAR
DEFINE Vowels ('A','E','I','O','U') : LetterSet
DECLARE Ch : CHAR
Ch ← 'E'
IF Ch IN Vowels THEN
   OUTPUT Ch, " is a vowel"
ENDIF

Pythonvowels = {'A', 'E', 'I', 'O', 'U'}
if ch in vowels:
    print(ch, "is a vowel")

💡 The guide defines only the declaration (TYPE … = SET OF …, DEFINE …). IN is a Playground convenience for membership.

§5 Common operations §5.1–5.6

INPUT/OUTPUT, arithmetic (+ − * / DIV MOD), relational (> < >= <= = <>), logic (AND OR NOT), the string functions the exam will always provide, and INT / RAND.

INPUT and OUTPUT (§5.1)

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CAIE pseudocodeDECLARE Answer : STRING
DECLARE Score, Lives : INTEGER
Score ← 120
Lives ← 3
INPUT Answer
OUTPUT Score
OUTPUT "You have ", Lives, " lives left"

Pythonanswer = input()
print(score)
print("You have", lives, "lives left")

💡 Several values separated by commas can be output in one statement.

Arithmetic (§5.2) — / always gives REAL; DIV and MOD for integers

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CAIE pseudocodeOUTPUT 7 / 2      // 3.5 (REAL even for integer operands)
OUTPUT 7 DIV 2    // 3 (quotient)
OUTPUT 7 MOD 2    // 1 (remainder)
OUTPUT (2 + 3) * 4  // use brackets to make order explicit

Pythonprint(7 / 2)   # 3.5
print(7 // 2)  # 3
print(7 % 2)   # 1
print((2 + 3) * 4)

Relational & logic operators (§5.3–5.4)

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CAIE pseudocodeDECLARE A, B : INTEGER
A ← 5
B ← 8
OUTPUT A > B, " ", A <= B, " ", A = 5, " ", A <> B
OUTPUT (A < B) AND NOT (B = 8)
OUTPUT (A > B) OR (B > A)

Pythonprint(a > b, a <= b, a == 5, a != b)
print((a < b) and not (b == 8))
print((a > b) or (b > a))

💡 Results are always BOOLEAN. Only AND, OR, NOT are used.

String functions provided in the exam (§5.5)

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CAIE pseudocodeOUTPUT RIGHT("ABCDEFGH", 3)     // "FGH"
OUTPUT LENGTH("Happy Days")      // 10
OUTPUT MID("ABCDEFGH", 2, 3)    // "BCD"  (start position, length)
OUTPUT LCASE('W')                // 'w'
OUTPUT UCASE('h')                // 'H'
OUTPUT "Summer" & " " & "Pudding"  // & concatenates

Python"ABCDEFGH"[-3:]          # RIGHT
len("Happy Days")          # LENGTH
"ABCDEFGH"[1:4]           # MID(s, 2, 3) → start index 1, length 3
'W'.lower(); 'h'.upper()
"Summer" + " " + "Pudding"

💡 These are the ONLY string functions defined in the 9618 guide. LCASE/UCASE take a CHAR; a non-letter is returned unchanged. 2210 additionally uses LEFT, SUBSTRING and applies UCASE/LCASE to strings.

Numeric functions (§5.6)

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CAIE pseudocodeOUTPUT INT(27.5415)      // 27 — the integer part
OUTPUT RAND(87) < 87     // RAND(x): random REAL from 0 up to (not including) x
OUTPUT INT(RAND(6)) + 1  // a dice roll 1–6

Pythonint(27.5415)
import random
random.random() * 87
random.randint(1, 6)

💡 2210 uses ROUND(x, places) and RANDOM() instead — both also run in the Playground.

§6 Selection §6.1–6.2

IF … THEN … [ELSE …] ENDIF and CASE OF … [OTHERWISE …] ENDCASE. There is no ELSEIF — nest IFs.

Nested IF — the guide's example (§6.1)

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CAIE pseudocodeDECLARE ChallengerScore, ChampionScore, HighestScore : INTEGER
DECLARE ChallengerName, ChampionName : STRING
ChallengerScore ← 90
ChampionScore ← 85
HighestScore ← 95
ChallengerName ← "Ayesha"
ChampionName ← "Bilal"
IF ChallengerScore > ChampionScore THEN
   IF ChallengerScore > HighestScore THEN
      OUTPUT ChallengerName, " is champion and highest scorer"
   ELSE
      OUTPUT ChallengerName, " is the new champion"
   ENDIF
ELSE
   OUTPUT ChampionName, " is still the champion"
   IF ChampionScore > HighestScore THEN
      OUTPUT ChampionName, " is also the highest scorer"
   ENDIF
ENDIF

Pythonif challenger_score > champion_score:
    if challenger_score > highest_score:
        print(challenger_name, "is champion and highest scorer")
    else:
        print(challenger_name, "is the new champion")
else:
    print(champion_name, "is still the champion")
    if champion_score > highest_score:
        print(champion_name, "is also the highest scorer")

CASE with OTHERWISE — the guide's example (§6.2)

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CAIE pseudocodeDECLARE Move : CHAR
DECLARE Position : INTEGER
Position ← 50
INPUT Move
CASE OF Move
   'W' : Position ← Position - 10
   'S' : Position ← Position + 10
   'A' : Position ← Position - 1
   'D' : Position ← Position + 1
   OTHERWISE : OUTPUT "Beep"
ENDCASE
OUTPUT Position

Pythonmatch move:
    case 'W': position -= 10
    case 'S': position += 10
    case 'A': position -= 1
    case 'D': position += 1
    case _: print("Beep")

💡 Cases are tested in sequence; the first that applies runs and control goes to after ENDCASE. OTHERWISE must be last.

CASE with ranges (§6.2)

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CAIE pseudocodeDECLARE Mark : INTEGER
Mark ← 67
CASE OF Mark
   80 TO 100 : OUTPUT "A"
   60 TO 79  : OUTPUT "B"
   40 TO 59  : OUTPUT "C"
   OTHERWISE : OUTPUT "U"
ENDCASE

Pythonif 80 <= mark <= 100: print("A")
elif 60 <= mark <= 79: print("B")
elif 40 <= mark <= 59: print("C")
else: print("U")

§7 Iteration §7.1–7.3

Count-controlled FOR … NEXT (inclusive, optional STEP), post-condition REPEAT … UNTIL (runs at least once), pre-condition WHILE … ENDWHILE (may run zero times).

Nested FOR loops — the guide's example (§7.1)

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CAIE pseudocodeCONSTANT MaxRow = 3
DECLARE Amount : ARRAY[1:3, 1:10] OF INTEGER
DECLARE Row, Column, RowTotal, Total : INTEGER
FOR Row ← 1 TO MaxRow
   FOR Column ← 1 TO 10
      Amount[Row, Column] ← Row * Column
   NEXT Column
NEXT Row
Total ← 0
FOR Row ← 1 TO MaxRow
   RowTotal ← 0
   FOR Column ← 1 TO 10
      RowTotal ← RowTotal + Amount[Row, Column]
   NEXT Column
   OUTPUT "Total for Row ", Row, " is ", RowTotal
   Total ← Total + RowTotal
NEXT Row
OUTPUT "The grand total is ", Total

Pythontotal = 0
for row in range(MAX_ROW):
    row_total = 0
    for column in range(10):
        row_total += amount[row][column]
    print("Total for Row", row + 1, "is", row_total)
    total += row_total
print("The grand total is", total)

💡 If value1 = value2 the body runs once; if value1 > value2 it does not run at all. Repeat the identifier after NEXT.

FOR with STEP (§7.1)

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CAIE pseudocodeDECLARE i : INTEGER
FOR i ← 10 TO 1 STEP -3
   OUTPUT i
NEXT i

Pythonfor i in range(10, 0, -3):
    print(i)

💡 The loop ends when the counter goes past value2. STEP may be negative.

REPEAT … UNTIL — the guide's example (§7.2)

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CAIE pseudocodeDECLARE Password : STRING
REPEAT
   OUTPUT "Please enter the password"
   INPUT Password
UNTIL Password = "Secret"
OUTPUT "Welcome"

Pythonwhile True:
    print("Please enter the password")
    password = input()
    if password == "Secret":
        break

💡 Statements run at least once; the condition is tested afterwards and TRUE ends the loop.

WHILE — the guide's example (§7.3)

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CAIE pseudocodeDECLARE Number : INTEGER
Number ← 25
WHILE Number > 9
   Number ← Number - 9
ENDWHILE
OUTPUT Number

Pythonwhile number > 9:
    number = number - 9

💡 9618 writes WHILE <condition> with no DO (2210 writes WHILE <condition> DO). Both run in the Playground.

§8 Procedures & functions §8.1–8.3

Procedures are CALLed as complete statements; functions RETURN a value and are used inside expressions (never with CALL). Parameters are BYVAL unless BYREF is stated. Functions must not take BYREF parameters.

Procedures with and without parameters — the guide's example (§8.1)

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CAIE pseudocodeCONSTANT Default = 100
DECLARE Size : INTEGER
 
PROCEDURE MoveForward(Distance : INTEGER)
   OUTPUT "forward ", Distance
ENDPROCEDURE
PROCEDURE Turn(Angle : INTEGER)
   OUTPUT "turn ", Angle
ENDPROCEDURE
PROCEDURE Square(Size : INTEGER)
   DECLARE Side : INTEGER
   FOR Side ← 1 TO 4
      CALL MoveForward(Size)
      CALL Turn(90)
   NEXT Side
ENDPROCEDURE
PROCEDURE DefaultSquare()
   CALL Square(100)
ENDPROCEDURE
 
Size ← 50
IF Size = Default THEN
   CALL DefaultSquare()
ELSE
   CALL Square(Size)
ENDIF

Pythondef square(size):
    for side in range(4):
        move_forward(size)
        turn(90)

def default_square():
    square(100)

if size == DEFAULT:
    default_square()
else:
    square(size)

Function — the guide's example (§8.2)

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CAIE pseudocodeDECLARE Distance : INTEGER
Distance ← 7
 
FUNCTION Max(Number1 : INTEGER, Number2 : INTEGER) RETURNS INTEGER
   IF Number1 > Number2 THEN
      RETURN Number1
   ELSE
      RETURN Number2
   ENDIF
ENDFUNCTION
 
OUTPUT "Penalty Fine = ", Max(10, Distance*2)

Pythondef max_(number1, number2):
    if number1 > number2:
        return number1
    return number2

print("Penalty Fine =", max_(10, distance * 2))

💡 RETURN executes immediately — later lines in the function are skipped. Do not write CALL before a function.

BYREF vs BYVAL — the guide's SWAP (§8.3)

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CAIE pseudocodePROCEDURE SWAP(BYREF X : INTEGER, Y : INTEGER)
   DECLARE Temp : INTEGER
   Temp ← X
   X ← Y
   Y ← Temp
ENDPROCEDURE
 
DECLARE A, B : INTEGER
A ← 1
B ← 2
CALL SWAP(A, B)
OUTPUT A, " ", B

Python# Python passes references to objects; ints are immutable,
# so return the new values instead:
def swap(x, y):
    return y, x
a, b = swap(a, b)

💡 BYREF: the procedure changes the caller's variable. BYVAL (the default): it works on a copy. One BYREF keyword covers the following parameters passed the same way.

§9 File handling §9.1–9.2

Text files: OPENFILE … FOR READ | WRITE | APPEND, READFILE, WRITEFILE, EOF, CLOSEFILE. Random files: OPENFILE … FOR RANDOM, SEEK, GETRECORD, PUTRECORD.

Copy a text file, replacing blank lines — the guide's example (§9.1)

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CAIE pseudocodeDECLARE LineOfText : STRING
// make FileA.txt first
OPENFILE "FileA.txt" FOR WRITE
WRITEFILE "FileA.txt", "first line"
WRITEFILE "FileA.txt", ""
WRITEFILE "FileA.txt", "third line"
CLOSEFILE "FileA.txt"
 
OPENFILE "FileA.txt" FOR READ
OPENFILE "FileB.txt" FOR WRITE
WHILE NOT EOF("FileA.txt")
   READFILE "FileA.txt", LineOfText
   IF LineOfText = "" THEN
      WRITEFILE "FileB.txt", " ----------------------------"
   ELSE
      WRITEFILE "FileB.txt", LineOfText
   ENDIF
ENDWHILE
CLOSEFILE "FileA.txt"
CLOSEFILE "FileB.txt"
OUTPUT "copied — see the Files panel"

Pythonwith open("FileA.txt") as src, open("FileB.txt", "w") as dst:
    for line in src:
        line = line.rstrip("\n")
        dst.write((" " + "-" * 28 if line == "" else line) + "\n")

💡 WRITE creates a new file (existing data lost); APPEND adds after existing data. EOF(file) is TRUE when no lines remain. Open a file in one mode at a time.

Random-access file — the guide's example, simplified (§9.2)

9618 only Run Run Python VB.NET · Java

CAIE pseudocodeTYPE Student
   DECLARE LastName : STRING
   DECLARE YearGroup : INTEGER
ENDTYPE
DECLARE Pupil, NewPupil : Student
DECLARE Position : INTEGER
 
OPENFILE "StudentFile.Dat" FOR RANDOM
FOR Position ← 10 TO 12
   Pupil.LastName ← "Pupil" & NUM_TO_STR(Position)
   Pupil.YearGroup ← 6
   SEEK "StudentFile.Dat", Position
   PUTRECORD "StudentFile.Dat", Pupil
NEXT Position
 
// move records 12..10 up one place, then insert at 10
FOR Position ← 12 TO 10 STEP -1
   SEEK "StudentFile.Dat", Position
   GETRECORD "StudentFile.Dat", Pupil
   SEEK "StudentFile.Dat", Position + 1
   PUTRECORD "StudentFile.Dat", Pupil
NEXT Position
NewPupil.LastName ← "Johnson"
NewPupil.YearGroup ← 6
SEEK "StudentFile.Dat", 10
PUTRECORD "StudentFile.Dat", NewPupil
CLOSEFILE "StudentFile.Dat"
OUTPUT "done — see the Files panel"

Pythonimport pickle, os
# Python: use a fixed record size and f.seek(pos * SIZE)
# with struct/pickle, or a shelve/dbm for keyed records.

💡 SEEK moves the file pointer to a record address; GETRECORD reads the record there into a variable of the right type; PUTRECORD overwrites the record there.

§10 Object-oriented programming §10.1–10.2

Methods and properties are public unless stated; PUBLIC/PRIVATE are used when access matters. Constructors are procedures named NEW. INHERITS for subclasses; SUPER for the parent's methods; NEW <class>(…) creates an object.

Methods and properties — the guide's example (§10.1)

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CAIE pseudocodeCLASS PlayerClass
   PRIVATE Attempts : INTEGER
   PUBLIC PROCEDURE NEW()
      Attempts ← 3
   ENDPROCEDURE
   PUBLIC PROCEDURE SetAttempts(Number : INTEGER)
      Attempts ← Number
   ENDPROCEDURE
   PUBLIC FUNCTION GetAttempts() RETURNS INTEGER
      RETURN Attempts
   ENDFUNCTION
ENDCLASS
 
DECLARE Player : PlayerClass
Player ← NEW PlayerClass()
Player.SetAttempts(5)
OUTPUT Player.GetAttempts()

Pythonclass Player:
    def __init__(self):
        self.__attempts = 3
    def set_attempts(self, number):
        self.__attempts = number
    def get_attempts(self):
        return self.__attempts

player = Player()
player.set_attempts(5)
print(player.get_attempts())

💡 Methods are called with dot notation: Player.SetAttempts(5). A private attribute can only be reached through public methods.

Constructors and inheritance — the guide's Pet/Cat example (§10.2)

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CAIE pseudocodeCLASS Pet
   PRIVATE Name : STRING
   PUBLIC PROCEDURE NEW(GivenName : STRING)
      Name ← GivenName
   ENDPROCEDURE
   PUBLIC FUNCTION GetName() RETURNS STRING
      RETURN Name
   ENDFUNCTION
ENDCLASS
 
CLASS Cat INHERITS Pet
   PRIVATE Breed : STRING
   PUBLIC PROCEDURE NEW(GivenName : STRING, GivenBreed : STRING)
      SUPER.NEW(GivenName)
      Breed ← GivenBreed
   ENDPROCEDURE
   PUBLIC FUNCTION Describe() RETURNS STRING
      RETURN GetName() & " is a " & Breed
   ENDFUNCTION
ENDCLASS
 
DECLARE MyCat : Cat
MyCat ← NEW Cat("Kitty", "Shorthaired")
OUTPUT MyCat.Describe()

Pythonclass Pet:
    def __init__(self, given_name):
        self.__name = given_name
    def get_name(self):
        return self.__name

class Cat(Pet):
    def __init__(self, given_name, given_breed):
        super().__init__(given_name)
        self.__breed = given_breed
    def describe(self):
        return f"{self.get_name()} is a {self.__breed}"

my_cat = Cat("Kitty", "Shorthaired")
print(my_cat.describe())

💡 Object creation: <object name> ← NEW <class name>(<param1>, <param2> …). 2026 guide typo: Breed was INTEGER; 2027–29 corrects it to STRING.

Beyond the guide: exception handling (A2 §20.3) 9618 syllabus §20.3

The official guide has no exception syntax because §20.3 is examined in Python, VB.NET or Java (Paper 4). When you plan in pseudocode, use TRY … EXCEPT … ENDTRY — it is the accepted form and the Playground runs it.

TRY … EXCEPT … ENDTRY

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CAIE pseudocodeDECLARE Entry : STRING
DECLARE N : INTEGER
INPUT Entry
TRY
   N ← STR_TO_NUM(Entry)
   OUTPUT 100 / N
EXCEPT
   OUTPUT "Error: ", ERRORMESSAGE()
ENDTRY
OUTPUT "Still running"

Pythontry:
    n = int(entry)
    print(100 / n)
except Exception as e:
    print("Error:", e)
print("Still running")

💡 The EXCEPT block runs only if a statement inside TRY raises a runtime error (division by zero, failed conversion, index out of range, file not open…). Validation prevents predictable bad input; exception handling deals with what still goes wrong. ERRORMESSAGE() is a Playground convenience for the caught message.

2210 (O Level) differences 2210 syllabus

O Level / IGCSE pseudocode (2210 / 0478 syllabus for 2026–2028, version 6) follows the same style and applies to exams up to November 2028; the 2029–2031 O Level syllabus uses Python only. Differences you must know for Paper 2:

2210 string & maths library routines

2210 only Run Run Python VB.NET · Java

CAIE pseudocodeOUTPUT LENGTH("Computer")           // 8
OUTPUT SUBSTRING("Computer", 1, 4)  // "Comp" (start, length)
OUTPUT UCASE("hello")               // "HELLO" — whole strings in 2210
OUTPUT LCASE("HELLO")
OUTPUT ROUND(3.14159, 2)            // 3.14
OUTPUT RANDOM() <= 1                // random number between 0 and 1 inclusive
OUTPUT 17 DIV 5, " ", 17 MOD 5      // 3 2

Pythonlen("Computer")
"Computer"[0:4]
"hello".upper()
round(3.14159, 2)
import random; random.random()
17 // 5, 17 % 5

2210 operators — the syllabus names (v4)

2210 only Run Run Python VB.NET · Java

CAIE pseudocodeDECLARE Pi, Radius : REAL
Pi ← 3.14
Radius ← 2
// Arithmetic: +  –  *  /  ^ (raised to the power of)
OUTPUT Pi * Radius ^ 2
// Integer division operators MOD and DIV
OUTPUT DIV(10, 3), " ", MOD(10, 3)
// Relational: =  <  <=  >  >=  <> (not equal to)
OUTPUT Radius <> 3
// Logical: AND  OR  NOT only
OUTPUT (Radius > 1) AND NOT (Radius > 5)

Pythonpi = 3.14
radius = 2
print(pi * radius ** 2)
print(10 // 3, 10 % 3)
print(radius != 3)
print(radius > 1 and not radius > 5)

💡 Version 4 of the 2026–28 syllabus (June 2025) renamed the operator groups: arithmetic, relational and logical operators, with ^ "raised to the power of" and MOD / DIV as the integer division operators (written DIV(10, 3) in the syllabus; 10 DIV 3 also runs). Relational results are always BOOLEAN.

2210 ROUND — what the syllabus says (v6)

2210 only Run Run Python VB.NET · Java

CAIE pseudocodeDECLARE Price : REAL
DECLARE Value : INTEGER
Price ← 12.456
OUTPUT ROUND(Price, 1)       // 12.5
OUTPUT ROUND(Price * 2, 0)   // 25 — an expression works too
Value ← ROUND(RANDOM() * 6, 0)  // a whole number between 0 and 6
OUTPUT Value >= 0 AND Value <= 6

Pythonprice = 12.456
print(round(price, 1))
print(round(price * 2))
import random
value = round(random.random() * 6)

💡 ROUND(<identifier> or <expression>, <places>) returns the value rounded to places decimal places. Version 6 (Sept 2026) states the value should be a REAL and places an INTEGER. The Playground rounds halves away from zero (2.5 → 3), errors if places is not a whole number or is negative, and warns if you round something that is already an INTEGER.

2210 procedures and functions — up to three parameters (v4)

2210 only Run Run Python VB.NET · Java

CAIE pseudocodeFUNCTION Volume(Length : INTEGER, Width : INTEGER, Height : INTEGER) RETURNS INTEGER
   RETURN Length * Width * Height
ENDFUNCTION
 
PROCEDURE Line(Size : INTEGER)
   DECLARE Count : INTEGER
   FOR Count ← 1 TO Size
      OUTPUT '-'
   NEXT Count
ENDPROCEDURE
 
CALL Line(3)
OUTPUT Volume(2, 3, 4)

Pythondef volume(length, width, height):
    return length * width * height

def line(size):
    for count in range(size):
        print('-')

line(3)
print(volume(2, 3, 4))

💡 Version 4 of the 2026–28 syllabus (June 2025): procedures and functions may have up to three parameters. O Level has no BYREF / BYVAL — parameters are passed by value and each argument must match its parameter's data type. Procedures are CALLed; functions are used in an expression, never with CALL.

2210 WHILE uses DO; totalling & counting pattern

2210 only Run VB.NET · Java

CAIE pseudocodeDECLARE Total, Count, Num : INTEGER
Total ← 0
Count ← 0
INPUT Num
WHILE Num <> -1 DO
   Total ← Total + Num
   Count ← Count + 1
   INPUT Num
ENDWHILE
OUTPUT "Total ", Total, " Count ", Count

Pythontotal = count = 0
num = int(input())
while num != -1:
    total += num
    count += 1
    num = int(input())

💡 Sentinel loops: INPUT before the loop and again at the end of the body.

2210 file handling

2210 only Run Run Python VB.NET · Java

CAIE pseudocodeDECLARE Line : STRING
OPENFILE "data.txt" FOR WRITE
WRITEFILE "data.txt", "Zak"
CLOSEFILE "data.txt"
OPENFILE "data.txt" FOR READ
READFILE "data.txt", Line
CLOSEFILE "data.txt"
OUTPUT Line

Pythonwith open("data.txt", "w") as f: f.write("Zak\n")
with open("data.txt") as f: line = f.readline().rstrip()