Lesson 4.2.1.2

4.2.1.2 Single- and multi-dimensional arrays Quiz: AQA Computer Science, Unit 2

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 4.2.1.2, Single- and multi-dimensional arrays: 20 multiple choice questions for the AQA Computer Science (7517), Unit 2: Fundamentals of data structures, written with Revision Ninja.

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The 20 questions

  1. What is a one-dimensional array?

    • A list of files on a disk, with each file stored at a numbered position in the directory
    • A variable holding a memory address, which points to the first element of a block in memory
    • A record with fields of different types, which groups related values under one shared name
    • A set of elements of the same data type indexed by a single integer

  2. A one-dimensional array is a useful way to represent which mathematical object?

    • A graph
    • A binary tree
    • A vector
    • A hash function

  3. A two-dimensional array is a useful way to represent which mathematical object?

    • A queue
    • A dictionary
    • A stack
    • A matrix

  4. An array is declared with indexes 0 to 9. How many elements does it hold?

    • 10
    • 9
    • 0
    • 11

  5. A 3 by 4 array has 3 rows and 4 columns. How many elements does it hold?

    • 12
    • 3
    • 7
    • 34

  6. What does an n-dimensional array require to locate an element?

    • A tuple of n integers as the index
    • No index at all, because the element is found by scanning the whole array from its start
    • A single string key, which is looked up in a table to find the position of the element
    • A pointer to a record, which holds the address of the start of the array in memory

  7. An array scores holds the values 4, 7, 2 and 9 at indexes 0 to 3. What is scores[2]?

    • 9
    • 4
    • 7
    • 2

  8. A 2D array grid has rows 0 to 2 and columns 0 to 3. What is the value of grid[1][2] if row 1 is 5, 6, 7, 8?

    • 6
    • 5
    • 7
    • 8

  9. A loop sums all 10 elements of a one-dimensional array. How many additions does it perform?

    • 1
    • 9
    • 10
    • 11

  10. An array holds the values 3, 8 and 5 at indexes 0 to 2. What is the largest value in the array?

    • 5
    • 3
    • 8
    • 16

  11. Why must all the elements of an array have the same data type?

    • So that each element occupies the same amount of storage and can be accessed by index
    • So the array can be saved as a text file only, since binary data cannot be stored in arrays
    • Because records must be stored in arrays, so every element is a record with the same fields
    • Because arrays cannot store numbers, so each element must hold text in a fixed format

  12. A program uses a one-dimensional array to store the 12 months' sales figures. Which index is used for January if indexing starts at 0?

    • 11
    • 0
    • 1
    • 12

  13. A 2D array representing a 5 by 5 board needs what index to reach the centre cell if indexing starts at 0?

    • [1][1]
    • [4][4]
    • [5][5]
    • [2][2]

  14. Which statement describes a multi-dimensional array correctly?

    • It can only have one index, which is why it is used only for lists of single values
    • It is the same as a linked list, with each element pointing to the next element in order
    • It holds elements of different types in one index, so a single position stores many values
    • It holds elements indexed by several integers, such as row and column

  15. A program stores a timetable as a 5 by 6 array, with 5 days and 6 periods. What does each element represent?

    • A student name only, which is recorded against the day and period of each class taken
    • A lesson for a particular day and period
    • A day of the week only, with the period stored separately in a second array of the same size
    • A constant value for the school, which is the same for every day and every period of the week

  16. A one-dimensional array of 100 elements is used where indexes run 0 to 99. What is the index of the last element?

    • 99
    • 100
    • 1
    • 98

  17. What is an advantage of arrays for storing a list of similar values?

    • Arrays store values in the order of their data types, grouping all integers before all text
    • Arrays automatically sort their values, so the largest value is always found at index zero
    • Elements can be accessed directly by index without searching from the start
    • Arrays cannot be changed once created, so the values are protected from later accidental change

  18. Why is an array sometimes described as equivalent to other structures in some languages?

    • Arrays and trees store data in the same way, with each value placed in a node of a binary tree
    • Arrays are always the same as hash tables, so keys and values are both stored in each slot
    • Many languages offer lists or other indexed collections that do the same job
    • Arrays and files are identical, with each element stored as one line of a text file on disk

  19. A program reads the array index for an element from the user. Why must the index be checked?

    • An index outside the array bounds causes an error or accesses the wrong data
    • Indexes must always be negative, so the program must reject every positive value entered
    • The check is not needed for arrays, because the language rejects any index that is out of range
    • Indexes can only be strings, so any number typed by the user must be converted to text first

  20. A program stores a 3 by 3 grid in a two-dimensional array indexed from 0. Which index pair locates the middle value?

    • [1][1]
    • [0][1]
    • [2][2]
    • [3][3]

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