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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 631 exam-style questions, each with its mark scheme and example answers. Print it, or answer it on paper and then open the mark schemes. Or browse the questions by topic.

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5 questions · 9 marks

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1Short recall2 marksTranslators Swap Remove

An interpreter is a type of translator.

Define the term interpreter.

[2 marks]
Mark scheme

Award one mark for any of the following up to a maximum of two marks:

  • Translates/converts (high-level/source) code one line/statement at a time (1)
  • Translates/converts the code and executes/runs each line as it goes (1)
  • Executes/runs each line/statement immediately after it is translated (1)
  • Reports/stops with an error message as soon as a syntax error is found (1)

Allow 'runs' for executes, 'converts' for translates and 'instruction' for line/statement

Do not accept translates the whole program before it is run

Do not accept produces/creates object code, an executable file or machine code that is saved

Example answers and how they were marked
Full marks2/2

An interpreter is a program that translates high-level code line by line. Each line is run as soon as it has been translated, so any errors are shown straight away.

Why: Line-by-line translation (1) and each line executed immediately (1); the point about errors would be a third creditworthy point but the maximum is two.

Some marks1/2

An interpreter translates code one line at a time.

Why: Line-by-line translation (1); no point for immediate execution.

No marks0/2

An interpreter translates the whole program before it is run.

Why: Near-miss describing a compiler; the scheme's 'Do not accept' line rules out whole-program translation.

2Short recall2 marksLow and High Level Languages Swap Remove

Programs written in a high-level language are often machine independent.

Define the term machine independence.

[2 marks]
Mark scheme

Award one mark for any of the following up to a maximum of two marks:

  • The (same) program/source code can run on different types/makes of computer/processor (1)
  • With few/no changes (to the program code) (1)
  • The same source code can be translated for each type of processor (1)
  • A different compiler/interpreter is used for each type of processor (1)
  • The program does not depend on one specific type of processor/hardware (1)
  • Only one version of the program needs to be written/kept (1)
  • The program is portable between different computers (1)

Allow 'different computers' as meaning different types of computer/processor.

Do not accept a program that will only run on one type of computer / the computer it was written on.

Do not accept written in machine code/binary, is translated into machine code, compiled/interpreted, is a low-level language.

Example answers and how they were marked
Full marks2/2

The same program can run on different types of computer (1) without being changed (1).

Why: Two creditworthy parts: runs on different types/makes of computer/processor (1); with few/no changes (1).

Some marks1/2

A program can run on different computers.

Why: Creditworthy point: can run on different types/makes of computer/processor (1), with 'different computers' allowed by the guidance. No second part about changes or translation.

No marks0/2

A program is written in machine code so the computer can understand it.

Why: Misconception: machine code is not machine independence; the mark scheme does not accept this, and no other creditworthy point is given.

3Short recall1 markTranslators Swap Remove

A compiler translates programs written in a high-level language.

State how much of a program a compiler translates before the program is run.

[1 mark]
Mark scheme

Award one mark for:

  • The whole program (before it is run) (1)

Allow all of the code/the entire program/the whole program in one go

Do not accept one line/statement at a time or each line as it is executed

Do not accept translating only the lines that contain errors

Example answers and how they were marked
Full marks1/1

The whole program, before it is run.

Why: Whole program translated before it is run (1).

No marks0/1

It translates the program one line at a time.

Why: Describes an interpreter; the scheme does not accept line-by-line translation.

No marks0/1

It translates only the lines that contain errors.

Why: Not a compiler behaviour; the scheme does not accept translating only error lines.

4Explain2 marksTranslators Swap Remove

A programmer writes a program in a high-level language. The program is translated by a compiler.

Explain why a compiler must translate the whole program before any of it can be executed.

[2 marks]
Mark scheme

Award up to two marks for a linked explanation such as:

  • The compiler produces object code/machine code for the whole program (1) so there is no complete executable until every line has been translated (1)
  • The compiler translates all the source code before producing the object code (1) so the program cannot start until translation has finished (1)
  • The compiler checks the whole program for errors during translation (1) so all of the source code must be read before an executable can be produced (1)

For both marks, the expansion must follow/associate with the statement.

Allow 'in one go'/'all at once' for the translation point, but this does not earn the second mark unless it is linked to why the program cannot be executed until translation has finished.

A statement that the whole program is translated, with no linked reason about when the program can be executed, earns 1 mark only.

Do not accept 'a compiler is faster' or 'compiled code runs faster' on its own; this does not explain why translation must finish before execution.

Do not accept 'it translates and runs the program one line at a time', as this describes an interpreter.

Example answers and how they were marked
Full marks2/2

A compiler produces object code for the whole program, so there is no complete executable until every line has been translated.

Why: Object code for the whole program (1) linked to there being no complete executable until every line is translated (1).

Some marks1/2

A compiler translates the whole program in one go.

Why: Translation of the whole program only (1); no linked reason about when the program can be executed, so the second mark is not awarded.

No marks0/2

A compiler translates and runs the program one line at a time, so it stops when it finds an error.

Why: Confuses a compiler with an interpreter; nothing about translating the whole program before execution, so no creditworthy point.

5Explain2 marksTranslators Swap Remove

An interpreter translates and executes high-level code.

Explain why an interpreted program must be translated again each time it is run.

[2 marks]
Mark scheme

Award up to two marks for a linked explanation such as:

  • No object code/machine code file is stored/saved (1) so there is no translated program to run on the next occasion (1)
  • The translation is only temporary/is lost when the program ends (1) because each line is translated as the program runs (1)
  • No executable file is created/saved (1) so the whole program has to be translated again every time it is run (1)
  • The interpreter translates each line while the program is running (1) so nothing is kept that could be run without the interpreter (1)

For both marks, the expansion must follow/associate with the statement.

Do not accept 'it is interpreted' or 'it is not compiled' without saying that no object code/executable is stored/saved.

Do not accept 'the source code is high-level so it must be translated' or 'the source code has to be turned into machine code' on its own, as this is true of any translation.

Do not accept answers about the source code being deleted.

Example answers and how they were marked
Full marks2/2

The interpreter does not store an object code file, so there is no machine code file to run on the next occasion.

Why: No object code stored (1) linked to no translated program for the next run (1).

Some marks1/2

No object code is saved.

Why: Point that nothing is stored (1) but no linked reason saying why this means the program must be translated again.

No marks0/2

It has to be translated again because the interpreter deletes the source code after each run.

Why: Incorrect: the interpreter does not delete the source code; no mark scheme point.

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