IGCSE Computer Science 0478 · Topic 8

Identify errors in given algorithms and suggest: past paper questions

19 real questionsasked in 6 of the last 10 exam series2021–2026usually: Write, Identify, State, Explain, Tick

Real questions on identify errors in given algorithms and suggest

The newest 19 of 19 written questions. Open one to see it on the real paper.

0478/21 · May/June 2026 · Q5a[2]
Write the pseudocode to generate a whole random number between 1 and 1000 inclusive and store it in the variable GeneratedNumber
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0478/21 · May/June 2026 · Q11[5]
The function Power(FirstNumber, SecondNumber) returns the value of FirstNumber raised to the power of SecondNumber. FirstNumber and SecondNumber are integers. Write pseudocode statements to: • • define the function call the function with the variables A and B and store the return value in the variable Value function de...
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0478/22 · May/June 2026 · Q5a[4]
error 1 line number correction error 2 line number correction (a) Identify the line numbers of four errors in the pseudocode and suggest corrections. error 4 line number correction correction error 3 line number
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0478/23 · October/November 2025 · Q5b[2]
The algorithm does not work correctly. State the reason why the algorithm does not work as expected and explain how the algorithm could be corrected. Any code used must be fully explained. Reason Correction
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0478/23 · October/November 2025 · Q6c[6]
Write the algorithm in pseudocode.
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0478/23 · October/November 2025 · Q7a[3]
Identify the line numbers of the three errors in the pseudocode and suggest a correction for each error. Correction Error 2 line number Correction Error 1 line number Correction Error 3 line number
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0478/23 · October/November 2025 · Q9b(i)[5]
Write pseudocode statements to: • • define the procedure with the parameter store the name of the person in the file.
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0478/23 · October/November 2025 · Q9b(ii)[2]
Write the pseudocode that uses the procedure StoreData() to store the name ‘Suella’ in the file People.txt
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0478/21 · May/June 2025 · Q5[4]
Two library routines used in programming are MOD and DIV. State the purpose of each of the library routines. Give one example pseudocode statement for each of the library routines. MOD purpose Example pseudocode DIV purpose Example pseudocode
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0478/22 · February/March 2025 · Q6a[5]
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
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0478/22 · February/March 2025 · Q6b[2]
Write the pseudocode statement to output the average of the numbers, rounded to two decimal places.
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0478/22 · February/March 2025 · Q6c[4]
Explain how you could change the corrected algorithm so that it also finds the smallest number that was input and outputs its value at the end. Any code used must be fully explained.
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0478/22 · February/March 2025 · Q7c(i)[3]
Explain how you would change the algorithm to prevent the problems described.
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0478/22 · May/June 2024 · Q7b[3]
the line numbers of the three errors in the pseudocode and suggest a correction for each error.
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0478/21 · October/November 2023 · Q1[1]
one box to show which operator means less than or equal to.
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0478/23 · October/November 2023 · Q5a[3]
Identify the three errors in the pseudocode and suggest corrections. Error Correction Error Correction Error Correction
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0478/23 · October/November 2021 · Q2a[4]
Find the four errors in the pseudocode and write a correction for each error. Error Correction Error Correction Error Correction Error Correction
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0478/23 · October/November 2021 · Q2b[3]
The pseudocode for this algorithm could be shortened by the use of a FOR … NEXT loop. Rewrite the algorithm using a FOR … NEXT loop.
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0478/23 · October/November 2021 · Q4[5]
The algorithm, shown by this flowchart, allows the input of examination marks for a class of students. A mark of 999 ends the process. If a mark is 40 or over then a pass grade is awarded. The number of pass grades is calculated for the whole class. If this is under 50% of the class, the class is offered extra help. ST...
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What examiners said

Most candidates were able to identify the correct purpose of MOD and DIV with only a few giving the correct pseudocode for MOD and DIV.
— Examiner report, May/June 2025, 0478/21 Q5 (Cambridge)

Most candidates were able to identify most of the errors in the given code.
— Examiner report, February/March 2025, 0478/22 Q6(a) (Cambridge)

A common error seen was that some candidates did not include the OUTPUT command in their answer. This was essential as the question required the output of the rounded number.
— Examiner report, February/March 2025, 0478/22 Q6(b) (Cambridge)

Practise this topic

Answer these questions online and get each one marked against the official mark scheme, with what you missed and how to fix it.

Practise identify errors in given algorithms and suggest

In the syllabus

1 0478.8.0.01 — Write and amend algorithms for given problems • Precision is required when writing algorithms,

Write and amend algorithms for given problems • Precision is required when writing algorithms,
e.g. x > y is acceptable but
x is greater than y is not acceptable • See section 4 for flowchart symbols • See section 4 for pseudocode

2 0478.8.0.02 — e.g. x > y is acceptable but

e.g. x > y is acceptable but

3 0478.8.0.03 — x is greater than y is not acceptable • See section 4 for flowchart symbols • See section 4 for pseudocode

x is greater than y is not acceptable • See section 4 for flowchart symbols • See section 4 for pseudocode

4 0478.8.1.01 — Understand and use arithmetic, relational • Arithmetic, limited to:

Understand and use arithmetic, relational • Arithmetic, limited to:
– + – – – / – * – ^ (raised to power of) – MOD – DIV • Relational, limited to: – = – < – <= – > – >= – <> (not equal to) • Logical, limited to: – AND – OR – NOT
Understand and use nested statements • Including nested selection and iteration • Candidates will not be required to write more than three levels of nested statements
(a) Understand what is meant by procedures,
Define and use procedures and functions, • Procedures and functions may have up to three
parameters
Understand and use local and global
Understand and use library routines • Including: – MOD – DIV – ROUND – RANDOM
Understand how to create a maintainable • Including appropriate use of:
– meaningful identifiers – the commenting feature provided by the programming language – procedures and functions – relevant and appropriate commenting of syntax • Use meaningful identifiers for: – variables – constants – arrays – procedures and functions

5 0478.8.1.02 — – + – – – / – * – ^ (raised to power of) – MOD – DIV • Relational, limited to: – = – < – <= – > – >= – <> (not equal to) • Logical, limited

– + – – – / – * – ^ (raised to power of) – MOD – DIV • Relational, limited to: – = – < – <= – > – >= – <> (not equal to) • Logical, limited to: – AND – OR – NOT

6 0478.8.1.03 — Understand and use nested statements • Including nested selection and iteration • Candidates will not be required to write more than three l

Understand and use nested statements • Including nested selection and iteration • Candidates will not be required to write more than three levels of nested statements

7 0478.8.1.04 — (a) Understand what is meant by procedures,

(a) Understand what is meant by procedures,

8 0478.8.1.05 — Define and use procedures and functions, • Procedures and functions may have up to three

Define and use procedures and functions, • Procedures and functions may have up to three

9 0478.8.1.06 — parameters

parameters

10 0478.8.1.07 — Understand and use local and global

Understand and use local and global

11 0478.8.1.08 — Understand and use library routines • Including: – MOD – DIV – ROUND – RANDOM

Understand and use library routines • Including: – MOD – DIV – ROUND – RANDOM

12 0478.8.1.09 — Understand how to create a maintainable • Including appropriate use of:

Understand how to create a maintainable • Including appropriate use of:

13 0478.8.1.10 — – meaningful identifiers – the commenting feature provided by the programming language – procedures and functions – relevant and appropriate

– meaningful identifiers – the commenting feature provided by the programming language – procedures and functions – relevant and appropriate commenting of syntax • Use meaningful identifiers for: – variables – constants – arrays – procedures and functions

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