AQA AS COMPUTER SCIENCE QUESTION PAPER 1 2020 IB/G/Jun20/E16 AS COMPUTER SCIENCE Paper 1

7516/1

IB/G/Jun20/E16

AQA AS COMPUTER SCIENCE

QUESTION PAPER 1 2020

7516/1

IB/G/Jun20/E16

AS

COMPUTER SCIENCE

Paper 1

Tuesday 19 May 2020 Morning Time allowed: 1 hour 45 minutes

Materials

For this paper you must have:

• a computer • a printer • appropriate software • the Electronic Answer Document • an electronic version and a hard copy of the Skeleton Program • an electronic version of the Data Files • an electronic version and a hard copy of the Preliminary Material.You must not use a calculator.

Instructions • Type the information required on the front of your Electronic Answer Document.• Before the start of the examination make sure your Centre Number, Candidate Name and Candidate Number are shown clearly in the footer of every page (not the front cover) of your Electronic Answer Document.• Enter your answers into the Electronic Answer Document.• Answer all questions.• Save your work at regular intervals.

Information • The marks for questions are shown in brackets.• The maximum mark for this paper is 75.• No extra time is allowed for printing and collating.• The question paper is divided into three sections.

Advice

You are advised to allocate time to each section as follows:

Section A – 20 minutes; Section B – 25 minutes; Section C – 60 minutes.

At the end of the examination Tie together all your printed Electronic Answer Document pages and hand them to the Invigilator.

Warning It may not be possible to issue a result for this paper if your details are not on every page of your Electronic Answer Document.

2 IB/G/Jun20/7516/1

Section A

You are advised to spend no more than 20 minutes on this section.

Enter your answers to Section A in your Electronic Answer Document. You must save this document at regular intervals.

Question 3 in this section asks you to write program code starting from a new program/project/file.

You are advised to save your program at regular intervals.

State two examples of work that you would expect to undertake during the analysis stage of software development.[2 marks]

A sentinel value is a special value after the end of a series of data values. It is a terminator for the series of data values but is not treated as part of the series. A sentinel value is used when you do not know how many data values are in the series.

The algorithm, represented using pseudo-code in Figure 1, is an attempt at a method to add numbers that are input as a series terminated by the sentinel value -1

X  0

Figure 1 Result  0

WHILE X ≠ -1

INPUT X

Result  Result + X

ENDWHILE

OUTPUT Result

• 1

• 2

3 IB/G/Jun20/7516/1

1 2

. Complete Table 1 by hand-tracing the algorithm in Figure 1. You may not need to use all the rows in Table 1.

The first row of Table 1 has already been completed for you.

The sequence of numbers for input is: 4, 6, 3, 2, -1

Table 1

X Result Output

• 0 -

Copy the contents of all the unshaded cells in Table 1 into your Electronic Answer Document.[3 marks]

. Comment on the result of the trace and describe how the algorithm should be modified.[2 marks]

Turn over for the next question

Turn over ►

• 0
• 0