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Edexcel GCSE Computer Science (1CP2) Exam Questions

Build a practice paper from 693 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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3 questions · 5 marks

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1Multiple choice1 markTranslators Swap Remove

A compiler translates source code into machine code.

Identify why a compiled program can be run on a computer that does not have the compiler installed.

[1 mark]
  • AThe code is translated again each time it is run
  • BThe code is translated one line at a time
  • CThe object code is saved as a separate file
  • DThe source code is saved with the program
Mark scheme
  • C The object code is saved as a separate file (1)
  • The only correct answer is C. The correct answer is the object code is saved as a separate file.
  • A is not correct because a compiled program is not translated again when it is run
  • B is not correct because translating one line at a time is how an interpreter works
  • D is not correct because the source code is not needed to run a compiled program
Example answers and how they were marked
Full marks1/1

C The object code is saved as a separate file

Why: Selected the saved object code, which can be run without the compiler being present (1).

No marks0/1

D The source code is saved with the program

Why: Near miss: it is the object code, not the source code, that is saved and run on another computer.

No marks0/1

B The code is translated one line at a time

Why: Confuses a compiler with an interpreter: a compiled program is translated as a whole and is not translated again when it is run.

2Describe2 marksTranslators Swap Remove

A high-level program must be translated into machine code before it can be run.

Describe how a compiler and an interpreter differ in when the translated code is executed.

[2 marks]
Mark scheme

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

  • The interpreter executes each line as soon as it has been translated (1) so translation and execution happen together/at the same time (1)
  • The compiler translates the whole program first (1) and the machine code is run later/separately (1)
  • The interpreter translates the code and runs it while the program is running (1) whereas the compiler does not run the code it produces (1)
  • The compiler produces translated code that is executed only after all the translation has finished (1) but the interpreter executes each line immediately (1)

Allow 'translates one line at a time' where it is linked to executing each line immediately.

Do not accept answers that only state that a compiler is faster/an interpreter is slower, without reference to when execution happens.

Do not accept answers that only give object code, error reporting or portability, without reference to when execution happens.

Do not accept the compiler executing the program as it translates it.

Example answers and how they were marked
Full marks2/2

The compiler translates the code first and the program is executed afterwards, but the interpreter executes each line as soon as it has been translated.

Why: Compiler translates the whole program first and it is executed afterwards (1) and interpreter executes each line as soon as it is translated (1).

Some marks1/2

The interpreter executes each line immediately after translating it.

Why: Correct interpreter timing (1); no comparison with when the compiler's translated code is executed.

No marks0/2

The compiler executes the program line by line as it translates it.

Why: Reverses the two translators; a compiler does not execute the program it translates, so no mark.

3Explain2 marksLow and High Level Languages Swap Remove

A program written in a high-level language can be run on computers that have different processors.

Explain one reason why this is possible.

[2 marks]
Mark scheme

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

  • The same source code can be used on different processors (1) because a compiler/interpreter for each processor translates it into that processor's machine code/instructions (1)
  • The program is machine/processor independent (1) because the code is translated into the machine code/instructions of each processor it is run on (1)
  • A different compiler/interpreter is used for each type of processor (1) so the same source code can be translated into each processor's machine code/instructions (1)
  • The program can be moved/copied to a computer with a different processor (1) because a compiler/interpreter that produces code for that processor exists (1)

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

Do not accept 'it is portable' without a linked reason about translation for different processors.

Do not accept 'it is easier to use/read/write' on its own without a linked reason about translation/processors.

Do not accept 'it is not written in binary'/'it is not machine code'/'it is not written in assembly language' as the reason without saying that the code is translated into each processor's machine code/instructions.

Do not accept the misconception that the program runs directly on any processor without being translated.

Example answers and how they were marked
Full marks2/2

The same source code can be used on different processors because a compiler for each type of processor translates it into that processor's machine code.

Why: Linked point (1) that the same source code is used and reason (1) that a compiler translates it into each processor's machine code.

Some marks1/2

It is machine independent because it is not written in binary.

Why: Point (1) that the program is machine independent, but the reason given does not say that the code is translated for each processor's machine code/instructions.

No marks0/2

Because it is easier to use than machine code.

Why: No point about translation or different processors; 'easier to use' is not accepted without a linked reason about translation/processors.

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