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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 514 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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4 questions · 6 marks

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1Short recall1 markTranslators Swap Remove

An interpreter translates high-level code.

State what happens to the translation of a program when an interpreter finds a syntax error.

[1 mark]
Mark scheme

Award one mark for any of the following:

  • Translation/execution stops (when the error is found) / the rest of the program is not translated/executed (1)

Allow stops/terminates/halts when the error is found

Do not accept shows/displays an error message on its own

Do not accept the whole program is translated and errors are reported at the end

Do not accept translates line by line on its own

Example answers and how they were marked
Full marks1/1

The translation stops as soon as the error is found, so the rest of the program is not translated.

Why: Translation stops when the error is found (1).

No marks0/1

An error message is displayed.

Why: Only an error message; it does not say translation stops, and the scheme does not accept a displayed error message on its own.

No marks0/1

The whole program is translated and all the errors are reported at the end.

Why: Describes a compiler; the scheme does not accept errors being reported at the end of translating the whole program.

2Short recall1 markLow and High Level Languages Swap Remove

A high-level language uses statements that look like English or maths.

State what a single statement in a high-level language is usually translated into.

[1 mark]
Mark scheme

Award one mark for:

  • Several/multiple machine code instructions (1)

The answer must refer to instructions.

Do not accept machine code on its own.

Do not accept binary on its own.

Do not accept 'one or more machine code instructions' as it does not show that one statement becomes several instructions.

Do not accept assembly code/compiled code/low-level code on their own.

Do not accept 'a line of code'/'a statement' as this repeats the question.

Example answers and how they were marked
Full marks1/1

Several machine code instructions

Why: Matches the creditworthy point that one high-level statement translates into several machine code instructions (1).

No marks0/1

Machine code

Why: Near-miss: gives the type of code but not that one statement becomes several instructions; mark scheme does not accept machine code on its own.

No marks0/1

Binary

Why: Misconception: high-level statements are translated into machine code instructions, not just binary; not accepted.

3Describe2 marksTranslators Swap Remove

A compiler and an interpreter both translate source code.

Describe one difference between what a compiler produces and what an interpreter produces.

[2 marks]
Mark scheme

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

  • A compiler produces object code/machine code/an executable (file) (1) whereas an interpreter produces no object code/translated file (1)
  • A compiler produces a machine code file (1) that can be run on its own/without the compiler/translator being present (1)
  • An interpreter produces no object code/file (1) because it translates and executes each line instead of saving translated code (1)
  • The compiler's output can be saved/stored (1) and run again later, while interpreted code has to be translated again each time it is run (1)

Allow binary for machine code.

Allow executable/an executable for object code.

Do not accept responses about translating the whole program, reporting errors or the speed of execution.

Do not accept 'the interpreter translates/executes one line at a time' on its own: this is how it translates, not what it produces. It earns the development only when linked to no object code/translated file being produced.

Do not accept the interpreter producing object code/an executable.

Example answers and how they were marked
Full marks2/2

A compiler produces object code, which is saved as a file, whereas an interpreter does not produce a file because it translates and executes each line.

Why: Compiler produces object code (1) contrasted with the interpreter producing no object code/translated file (1).

Some marks1/2

The compiler produces machine code.

Why: Machine code/object code produced (1); there is no contrast with the interpreter, so the development is not earned.

No marks0/2

The interpreter produces object code for each line it translates.

Why: Reverses the translators' outputs: the interpreter produces no object code, so nothing is creditworthy.

4Explain2 marksLow and High Level Languages Swap Remove

A programmer writes the same program in a low-level language and in a high-level language.

Explain one reason why the program written in the low-level language may run faster.

[2 marks]
Mark scheme

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

  • The programmer can choose the most efficient instructions/registers to use (1) so the program completes its task in fewer steps (1)
  • The programmer can optimise the code for the processor (1) because low-level instructions give direct control of registers/memory (1)
  • Each low-level instruction maps to one machine code instruction (1) so fewer instructions are executed than for the equivalent high-level code (1)
  • The translated code is smaller (1) so fewer instructions are fetched from memory and executed (1)

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

Do not accept 'it is low-level' / 'it is closer to machine code' / 'low-level code is faster' on its own without a reason why it makes the program run faster.

Do not accept 'high-level code has to be translated' / 'high-level code is interpreted' on its own without saying why that makes the program slower.

Do not accept 'the code is smaller' on its own without saying that this means fewer instructions are fetched/executed.

Do not accept 'it is easier to write' or 'quicker to type' as a reason for faster execution.

Example answers and how they were marked
Full marks2/2

The programmer can choose the most efficient instructions and registers to use (1) so the program completes its task in fewer steps (1).

Why: Linked point (1) of choosing efficient instructions/registers and reason (1) that the task is completed in fewer steps, so it runs faster.

Some marks1/2

Each low-level instruction maps to one machine code instruction (1) so the program is shorter to type.

Why: Point (1) that one low-level instruction maps to one machine code instruction, but being shorter to type does not explain why the program runs faster, so no second mark.

No marks0/2

Because it is closer to machine code.

Why: 'Closer to machine code' alone gives no reason why that makes the program run faster, and the mark scheme does not accept it on its own.

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