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Algorithm Design and Standard Methods: Question 1

Syllabus 7.4

Multiple choice 1 mark

A gym stores the number of visits made by each of its members during the last month in a one-dimensional (1D) array called Visits, which has 8 elements. The pseudocode algorithm below is run on this array.

DECLARE Visits : ARRAY[1:8] OF INTEGER
DECLARE Index : INTEGER
DECLARE Reward : INTEGER
Reward ← 0
FOR Index ← 1 TO 8
    IF Visits[Index] > 10 THEN
        Reward ← Reward + 1
    ENDIF
NEXT Index
OUTPUT Reward

What is the purpose of this algorithm?

Choose an answer to check it, then compare with the worked solution below.
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Worked solution

Step 1: Identify the variables and what each one holds

Visits holds one value per member (8 members in total). Reward starts at 0 before the loop runs, so it is being built up rather than storing a single fixed value read from the array.

Step 2: Trace what happens inside the loop

For every member in turn (Index from 1 to 8):

  • The algorithm checks IF Visits[Index] > 10 THEN.
  • Only when that condition is true does it execute Reward ← Reward + 1.

Crucially, the amount added to Reward is always exactly 1, never Visits[Index] itself. That single detail rules out totalling (option A), which would need Reward ← Reward + Visits[Index].

Step 3: Rule out the other standard methods

  • Totalling would add each member’s actual visit count to a running total, not the case here.
  • Finding a maximum would need a comparison against a variable holding the largest value seen so far (e.g. IF Visits[Index] > MaxSoFar THEN MaxSoFar ← Visits[Index]), and would output that variable, not a running total of “how many times”.
  • Finding an average would need a running total divided by the number of elements (8) at the end.

Step 4: Confirm what the algorithm actually does

Reward only ever increases by 1, and only when a member’s visits exceed 10. So after the loop, Reward holds a count of how many of the 8 members visited more than 10 times, exactly the standard “counting” method applied with a condition.

Final answer

  • The algorithm counts how many members made more than 10 visits, option B.