Cambridge IGCSE Computer Science (9-1) 0984 — 2025 May/June Paper 2 · Variant 2

[Turn over Cambridge IGCSE™(9–1) DC (DE) 366879/2 © UCLES 2025 This document has 16 pages. Any blank pages are indicated. * 8 6 4 7 4 2 8 8 5 4 * COMPUTER SCIENCE 0984/22 Paper 2 Algorithms, Programming and Logic May/June 2025 1 hour 45 minutes You must answer on the question paper. No additional materials are needed. INSTRUCTIONS ● Answer all questions. ● Use a black or dark blue pen. You may use an HB pencil for any diagrams or graphs. ● Write your name, centre number and candidate number in the boxes at the top of the page. ● Write your answer to each question in the space provided. ● Do not use an erasable pen or correction fluid. ● Do not write on any bar codes. ● Calculators must not be used in this paper. INFORMATION ● The total mark for this paper is 75. ● The number of marks for each question or part question is shown in brackets [ ]. ● No marks will be awarded for using brand names of software packages or hardware.

2 0984/22/M/J/25 © UCLES 2025 1 Tick (✓) one box to complete the description of abstraction. Abstraction is part of the analysis stage of the development life cycle. Abstraction means A testing the solution to the problem. B writing a program using program code. C defining the sub-systems that make up the problem. D removing details from the problem that are not relevant. [1] 2 A fence measuring 2 metres in height and 20 metres in length needs painting. The area of the fence needs to be calculated so that enough paint for the job is purchased. After the task is decomposed, there are three component parts: input, process and output. Three component parts and four example descriptions are shown. Draw one line from each component part to the most appropriate relevant description. Not all descriptions will be used. the height of the fence the length of the fence The amount of paint required is 40 square metres. The area of fence is calculated as 40 square metres. the colour of the paint process output input Component part Description [3] 3 A range check is used to validate that the input temperature is an integer between –100 and 0, inclusive. Suggest suitable normal, abnormal, extreme and boundary test data to test if this validation check is working correctly. Normal test data … Abnormal test data … Extreme test data … Boundary test data … [4]

3 0984/22/M/J/25 © UCLES 2025 [Turn over 4 (a) State one reason for using a verification check when inputting data. … … [1] (b) Write the pseudocode for an algorithm to perform a double entry verification check, using the following criteria: • Input 10 numbers and store them in the array Numbers[] • Input the same 10 numbers again; as each number is input, compare it with its corresponding number in the array Numbers[] ◦ if the numbers match, move on to the next number ◦ if the numbers do not match, display both numbers and ask for the number to be re-entered ◦ store the re-entered number in the corresponding array location and move on to the next number. • When all the numbers have been checked, display a message to say the check has been completed. You do not need to declare any arrays or variables for this algorithm. … … … … … … … … … … … … … … … [6]

4 0984/22/M/J/25 © UCLES 2025 5 This pseudocode algorithm should allow 500 names of people and their heights to be entered and stored in two one-dimensional (1D) arrays. The name of a person and the height of that person are in the same index in both the Names[] and the Heights[] arrays. The algorithm performs as follows: • at the start, the following data is entered: ◦ name of person ◦ height of person in cm • the data is stored in the relevant arrays • the heights of the people are totalled • the shortest person is found • at the end, the following is output: ◦ name of shortest person ◦ height of shortest person ◦ average height of all 500 people. 01 DECLARE Names : ARRAY[1:500] OF REAL 02 DECLARE Heights : ARRAY[1:500] OF REAL 03 DECLARE Shortest : REAL 04 DECLARE Total : REAL 05 DECLARE Counter : INTEGER 06 DECLARE Index : INTEGER 07 Shortest 500 08 Index 0 09 Total 100 10 FOR Counter 1 TO 500 11 INPUT Names[Index] 12 INPUT Heights[Counter] 13 Total Counter + Heights[Counter] 14 IF Heights[Counter] < Shortest 15 THEN 16 Shortest Heights[Counter] 17 Index Counter 18 ENDIF 19 NEXT Counter 20 OUTPUT "The shortest height is ", Heights 21 OUTPUT "The shortest person is ", Names[Index] 22 OUTPUT "The average height is ", Total / 500

5 0984/22/M/J/25 © UCLES 2025 [Turn over (a) Identify the line numbers of five errors in the pseudocode and suggest a correction for each error. Error 1 line number … Correction … … Error 2 line number … Correction … … Error 3 line number … Correction … … Error 4 line number … Correction … … Error 5 line number … Correction … … [5] (b) Write the pseudocode statement that will output the average height rounded to one decimal place. … … [2] (c) Explain how you could change the corrected algorithm so that it will also: • find the height of the tallest person. • output the height of the tallest person at the end of the algorithm. Any program statements used must be fully explained. … … … … … … … … [4]

6 0984/22/M/J/25 © UCLES 2025 6 This pseudocode is an algorithm. DECLARE Word : STRING DECLARE V1 : INTEGER DECLARE V2 : INTEGER DECLARE Number : INTEGER DECLARE Index : INTEGER DECLARE L1 : CHAR DECLARE L2 : CHAR DECLARE Continue : BOOLEAN INPUT Number FOR Index 1 TO Number INPUT Word Continue TRUE V1 1 V2 LENGTH(Word) WHILE Continue = TRUE AND V1 < V2 DO L1 SUBSTRING(Word, V1, 1) L2 SUBSTRING(Word, V2, 1) IF L1 <> L2 THEN Continue FALSE ELSE V1 V1 + 1 V2 V2 – 1 ENDIF ENDWHILE IF Continue = TRUE THEN OUTPUT "Successful" ELSE OUTPUT "NOT successful" ENDIF NEXT Index

7 0984/22/M/J/25 © UCLES 2025 [Turn over (a) Complete the trace table for the algorithm, using the input data: 2, RACECAR, TREAT Number Index Word Continue V1 V2 L1 L2 OUTPUT [6] (b) State the purpose of the algorithm on page 6. … … [1] (c) Explain how the algorithm knows when all the letters in the word have been checked so that it can stop checking. … … … … … … [3]

8 0984/22/M/J/25 © UCLES 2025 7 The flowchart shows an algorithm that is used to input 50 numbers. Each number is stored in the variable Value when it is input. Any number input that is less than or equal to –20 or greater than or equal to 50 is rejected and re-input. The accepted numbers are added together as they are entered and the total and average of these numbers are output at the end of the algorithm. (a) Complete the flowchart. Count START Yes No No Yes STOP 0 Total 0 [6]

9 0984/22/M/J/25 © UCLES 2025 [Turn over (b) Explain how you would alter the flowchart in 7(a) so that it will individually store each accepted value as it is entered and then output all the numbers, one after the other, outside of the loop that inputs values. You may include program statements or flowchart symbols in your answer, but they must be fully explained. … … … … … … … … … … [4]

10 0984/22/M/J/25 © UCLES 2025 8 (a) Draw the symbol for an XOR logic gate and complete the truth table for it. XOR logic gate symbol: Truth table: A B X 0 0 0 1 1 0 1 1 [2]

11 0984/22/M/J/25 © UCLES 2025 [Turn over (b) Consider the logic rules in the following table: Input Binary value Description A 0 operator not present 1 operator present B 0 ignition key present 1 ignition key not present C 0 operator code correct 1 operator code not correct A crane is a machine with a long arm used to lift heavy objects. The crane will only move: • if the operator is present and • either the ignition key is present, or the operator code is correct. The crane moving is represented by X = 1. (i) Write the logic expression for the crane moving. X = … [2] (ii) Complete the truth table for the crane moving. A B C Working space X 0 0 0 0 0 1 0 1 0 0 1 1 1 0 0 1 0 1 1 1 0 1 1 1 [4]

12 0984/22/M/J/25 © UCLES 2025 9 A database table, CapitalCity, stores data about capital cities from around the world. Field Description Identification a unique identifier Name the name of the city Country the name of the country in which the city is located Continent the name of the continent in which the city is located Population the number of people living in the city Founded the year the city was founded AverageIncome average income of the city’s population, in $, rounded to 2 decimal places Subway whether or not the city has an underground railway system (a) Complete the table by writing one appropriate field from CapitalCity for each data type. Each field must be different. Data type Field Boolean integer real text [2] (b) Complete the structured query language (SQL) statement to list only the name, country and population of all the cities in CapitalCity from the continent of Asia. SELECT … … CapitalCity WHERE … = … ; [4]

13 0984/22/M/J/25 © UCLES 2025 Due to an issue with Question 10, the question has been removed from the question paper.

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16 0984/22/M/J/25 © UCLES 2025 Permission to reproduce items where third-party owned material protected by copyright is included has been sought and cleared where possible. Every reasonable effort has been made by the publisher (UCLES) to trace copyright holders, but if any items requiring clearance have unwittingly been included, the publisher will be pleased to make amends at the earliest possible opportunity. To avoid the issue of disclosure of answer-related information to candidates, all copyright acknowledgements are reproduced online in the Cambridge Assessment International Education Copyright Acknowledgements Booklet. This is produced for each series of examinations and is freely available to download at www.cambridgeinternational.org after the live examination series. Cambridge Assessment International Education is part of Cambridge Assessment. Cambridge Assessment is the brand name of the University of Cambridge Local Examinations Syndicate (UCLES), which is a department of the University of Cambridge. BLANK PAGE

This document consists of 13 printed pages. © Cambridge University Press & Assessment 2025 [Turn over Cambridge IGCSE™ (9–1) COMPUTER SCIENCE 0984/22 Paper 2 Algorithms, Programming and Logic May/June 2025 MARK SCHEME Maximum Mark: 75 Published This mark scheme is published as an aid to teachers and candidates, to indicate the requirements of the examination. It shows the basis on which Examiners were instructed to award marks. It does not indicate the details of the discussions that took place at an Examiners’ meeting before marking began, which would have considered the acceptability of alternative answers. Mark schemes should be read in conjunction with the question paper and the Principal Examiner Report for Teachers. Cambridge International will not enter into discussions about these mark schemes. Cambridge International is publishing the mark schemes for the May/June 2025 series for most Cambridge IGCSE, Cambridge International A and AS Level components, and some Cambridge O Level components.

0984/22 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 2 of 13 Generic Marking Principles These general marking principles must be applied by all examiners when marking candidate answers. They should be applied alongside the specific content of the mark scheme or generic level descriptions for a question. Each question paper and mark scheme will also comply with these marking principles. GENERIC MARKING PRINCIPLE 1: Marks must be awarded in line with: • the specific content of the mark scheme or the generic level descriptors for the question • the specific skills defined in the mark scheme or in the generic level descriptors for the question • the standard of response required by a candidate as exemplified by the standardisation scripts. GENERIC MARKING PRINCIPLE 2: Marks awarded are always whole marks (not half marks, or other fractions). GENERIC MARKING PRINCIPLE 3: Marks must be awarded positively: • marks are awarded for correct/valid answers, as defined in the mark scheme. However, credit is given for valid answers which go beyond the scope of the syllabus and mark scheme, referring to your Team Leader as appropriate • marks are awarded when candidates clearly demonstrate what they know and can do • marks are not deducted for errors • marks are not deducted for omissions • answers should only be judged on the quality of spelling, punctuation and grammar when these features are specifically assessed by the question as indicated by the mark scheme. The meaning, however, should be unambiguous. GENERIC MARKING PRINCIPLE 4: Rules must be applied consistently, e.g. in situations where candidates have not followed instructions or in the application of generic level descriptors. GENERIC MARKING PRINCIPLE 5: Marks should be awarded using the full range of marks defined in the mark scheme for the question (however; the use of the full mark range may be limited according to the quality of the candidate responses seen). GENERIC MARKING PRINCIPLE 6: Marks awarded are based solely on the requirements as defined in the mark scheme. Marks should not be awarded with grade thresholds or grade descriptors in mind.

0984/22 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 3 of 13 Annotations guidance for centres Examiners use a system of annotations as a shorthand for communicating their marking decisions to one another. Examiners are trained during the standardisation process on how and when to use annotations. The purpose of annotations is to inform the standardisation and monitoring processes and guide the supervising examiners when they are checking the work of examiners within their team. The meaning of annotations and how they are used is specific to each component and is understood by all examiners who mark the component. We publish annotations in our mark schemes to help centres understand the annotations they may see on copies of scripts. Note that there may not be a direct correlation between the number of annotations on a script and the mark awarded. Similarly, the use of an annotation may not be an indication of the quality of the response. The annotations listed below were available to examiners marking this component in this series. Annotations Annotation Meaning Correct point Incorrect point Follow through Repetition Ignore Benefit of doubt given Content of response too vague Not answered question Omission Section not relevant Section incorrect Highlighter Highlights part of the answer or shows structure of complex answers Page or response seen by examiner AO2 mark AO3 mark Not enough Required item one

0984/22 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 4 of 13 Annotation Meaning Required item two Required item three Correct awarding one mark Correct awarding two marks Correct awarding three marks Correct awarding four marks Correct awarding five marks Correct awarding six marks Correct awarding seven marks Correct awarding eight marks Correct awarding nine marks Mark scheme abbreviations / separates alternative words / phrases within a marking point // separates alternative answers within a marking point underline actual word given must be used by candidate (grammatical variants accepted) max indicates the maximum number of marks that can be awarded ( ) the word / phrase in brackets is not required, but sets the context Note: No marks are awarded for using brand names of software packages or hardware.

0984/22 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 5 of 13 Question Answer Marks 1 D 1 Question Answer Marks 2 One mark for each correct line, max three Component part Example statements 3 Question Answer Marks 3 One mark per correct piece of test data, Normal test data: −50 (any integer value between 0 and −100, inclusive) Abnormal test data: 50 (any value outside the range 0 and −100, inclusive, or any non-numeric input and non-integers Extreme test data: 0 // −100 Boundary test data: 1 // 0 // −100 // −101 4 Question Answer Marks 4(a) To check that the value entered has not changed on input. 1 input process output the height of the fence the length of the fence The area of fence is calculated as 40 square metres. the colour of the paint The amount of paint required is 40 square metres.

0984/22 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 6 of 13 Question Answer Marks 4(b) One mark per mark point, max six MP1 At least one appropriate working loop MP2 First inputs of numbers all stored in array Numbers MP3 Correct second input made for each number MP4 Working selection statement to compare first and second inputs one at a time MP5 If numbers don’t match, appropriate output, including both values input and a message requiring re-input MP6 New input stored in current array location (replacing original input) MP7 Final output confirming completion, outside loop. For example, // variable and array declarations or initialisations // are not required for this question FOR Index  1 TO 10 INPUT Numbers[Index] NEXT Index FOR Index  1 TO 10 INPUT CheckNumber IF CheckNumber <> Numbers[Index] THEN OUTPUT CheckNumber, " and ", Numbers[Index], " do not match. Please re-enter the number. " INPUT Numbers[Index] ENDIF NEXT Index OUTPUT "The check has been completed." 6

0984/22 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 7 of 13 Question Answer Marks 5(a) One mark per mark point • Line 01 / DECLARE Names : ARRAY[1:500] OF REAL should be DECLARE Names : ARRAY[1:500] OF STRING • Line 09 / Total  100 should be Total  0 • Line 11 / INPUT Names[Index] should be INPUT Names[Counter] • Line 13 / Total  Counter + Heights[Counter] should be Total  Total + Heights[Counter] • Line 20 / OUTPUT "The shortest height is ", Heights should be OUTPUT "The shortest height is ", Shortest or OUTPUT "The shortest height is ", Heights[Index] 5 01 DECLARE Names : ARRAY[1:500] OF STRING 02 DECLARE Heights : ARRAY[1:500] OF REAL 03 DECLARE Shortest : REAL 04 DECLARE Total : REAL 05 DECLARE Counter : INTEGER 06 DECLARE Index : INTEGER 07 Shortest  500 08 Index  0 09 Total  0 10 FOR Counter  1 TO 500 11 INPUT Names[Counter] 12 INPUT Heights[Counter] 13 Total  Total + Heights[Counter] 14 IF Heights[Counter] < Shortest 15 THEN 16 Shortest  Heights[Counter] 17 Index  Counter 18 ENDIF 19 NEXT Counter 20 OUTPUT "The shortest height is ", Shortest 21 OUTPUT "The shortest person is ", Names[Index] 22 OUTPUT "The average height is ", Total / 500 5(b) One mark per mark point MP1 Output statement with correct calculation of average, or use of a variable average. MP2 Correct use of ROUND function set to 1 decimal place. For example, OUTPUT ROUND(Total / 500, 1) 2

0984/22 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 8 of 13 Question Answer Marks 5(c) One mark per statement, max four MP1 Declaration of new variable for tallest person / largest value at start of algorithm MP2 Initialisation of largest variable to a low number e.g. 0 MP3 New selection statement after input of height to compare it with current largest value MP4 If input of height is larger than current largest variable, it should become the new largest value MP5 Outside the loop, output the current value of the largest variable. 4 Question Answer Marks 6(a) One mark per mark point MP1 Correct Number and Index columns MP2 Correct Word column MP3 Correct Continue column MP4 Correct V1 and V2 column MP5 Correct L1 and L2 column MP6 Correct OUTPUT column Number Index Word Continue V1 V2 L1 L2 OUTPUT 2 1 RACECAR TRUE 1 7 R R 2 6 A A 3 5 C C 4 4 Successful 2 TREAT TRUE 1 5 T T 2 4 R A FALSE NOT successful 6 6(b) Finds words that read the same forwards and backwards. 1

0984/22 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 9 of 13 Question Answer Marks 6(c) One mark per mark point, max three MP1 Uses an index to mark the start and end of each word // uses V1 to mark the start of the word and V2 to mark the end MP2 After each check, these are moved to the next character in the word at each end of the word // V1 is incremented by 1 and V2 is decremented by 1 after each check. MP3 When the two indexes match or cross, the whole word has been checked // When V1 = V2 or V1 > V2, the whole word has been checked MP4 The algorithm will exit if it is found that two compared letters are not the same. 3

0984/22 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 10 of 13 Question Answer Marks 7(a) One mark per mark point, max six MP1 input Value MP2 correct check that Value is between −20 and 50, exclusive MP3 totalling values MP4 counting number of values MP5 checking Count = 50 / >= 50 MP6 output of total and average 6 7(b) One mark per statement MP1 Change INPUT Value so that it saves values into an array MP2 … using the counter as the index MP3 Outside the (first) loop, set up a loop that will iterate 50 times MP4 Use an output statement inside the (second) loop to output the contents of the array, using the counter as the index. 4 IS Count = 50 ? Yes STOP Yes No No Total  Total + Value Count  Count + 1 IS Value <= –20 OR Value >= 50 ? INPUT Value Total  0 START Count  0 OUTPUT Total/50 OUTPUT Total

0984/22 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 11 of 13 Question Answer Marks 8(a) One mark for the logic gate and one mark for the truth table XOR logic gate symbol: Truth table: A B X 0 0 0 0 1 1 1 0 1 1 1 0 2 8(b)(i) One mark per mark point MP1 A AND MP2 (NOT B OR NOT C) // NOT(B AND C) // (B NAND C) Or One mark per mark point MP3 A AND NOT B MP4 OR A AND NOT C Example answers (X =) A AND (NOT B OR NOT C) // A AND NOT (B AND C) // A AND (B NAND C) (X =) A AND NOT B OR A AND NOT C 2

0984/22 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 12 of 13 Question Answer Marks 8(b)(ii) Four marks for eight correct outputs Three marks for six or seven correct outputs Two marks for four or five correct outputs One mark for two or three correct outputs A B C X 0 0 0 0 0 0 1 0 0 1 0 0 0 1 1 0 1 0 0 1 1 0 1 1 1 1 0 1 1 1 1 0 4 Question Answer Marks 9(a) Two marks for all four fields correctly identified One mark for two or three fields correctly identified Data type Field Boolean Subway integer Population // Founded // Identification real AverageIncome text Name // Country // Continent // Identification 2 9(b) One mark per mark point MP1 All correct fields in SELECT MP2 Correct use of key word FROM MP3 Correct field in WHERE: Continent MP4 Correct criterion in WHERE: "Asia" // 'Asia' Correct code: SELECT Name, Country, Population FROM CapitalCity WHERE Continent = "Asia"; // 'Asia'; 4

0984/22 Cambridge IGCSE (9–1) – Mark Scheme PUBLISHED May/June 2025 © Cambridge University Press & Assessment 2025 Page 13 of 13 Question Answer Marks 10 Due to an issue with this question, the question has been removed from the question paper. 15