Computer Science · May / June 2026 · Paper 22 · Question 10
0478
As printed in the paper
The question as text
A program is required to record and analyse the daily rainfall in millimetres for one year. Assume a year has 365 days. The one-dimensional (1D) array y©´á©¨¨ is used to store the daily rainfall measurements. Write a program for the following requirements: • Initialise the array y©´á©¨¨ to zero. • Input the rainfall measurement in millimetres for each day and store it in the array. • Calculate the following statistics after all the inputs have been made for the year: â the total rainfall for the year in centimetres (1 centimetre = 10 millimetres), rounded to two decimal places â the mean average daily rainfall in millimetres, rounded to four decimal places â the total number of days with no rainfall â the longest number of consecutive days in which there was no rainfall. • Output all the calculated statistics with clear and appropriate messaging. • If the longest number of consecutive days in which there was no rainfall is 15 or more, output You must use pseudocode or program code and add comments to explain how your code works. All arrays, variables or constants used must be declared for this algorithm. All inputs and outputs must contain suitable messages.
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Show the answer and mark scheme
Use the tables for AO2 and AO3 below to award a mark in a suitable band using a best fit approach, then add up the total.
Marks are available for:
Data structures required with names as given in the scenario:
Arrays or lists Rainfall[]
Requirements (techniques)
R1 Declares of variables and array, initialises array, inputs daily rainfall in mm for a year and stores it in the array (declarations, initialisation, iteration, input, output). R2 Calculates the total rainfall for the year in cm rounded to 2 d.p., the mean average rainfall in mm rounded to 4 d.p., the number of days with no rainfall and the longest period of days with no rainfall (totalling, counting, iteration, rounding, selection, finding max).
R3 Outputs the total rainfall for the year in cm, the average rainfall, the number of days with no rainfall and the longest period of days with no rainfall. Determines if a drought occurred and outputs the result (output, selection).
Example 15-mark answer in pseudocode:
// array and variable declaration
DECLARE Rainfall : ARRAY[1:365] OF REAL
DECLARE Index : INTEGER
DECLARE TotalRain : REAL
DECLARE AverageRain : REAL
DECLARE NoRain : INTEGER
DECLARE DryDays : INTEGER
DECLARE MaxDryDays : INTEGER
// initialising array
FOR Index ← 1 TO 365
Rainfall[Index] ← 0
NEXT Index
// daily input of rainfall
FOR Index ← 1 TO 365
OUTPUT "Input the rainfall measurement for day ", Index INPUT Rainfall[Index]
NEXT Index
// finding the total and average rainfall
TotalRain ← 0
FOR Index ← 1 TO 365
TotalRain ← TotalRain + Rainfall[Index]
NEXT Index
// average daily rainfall to 4dp
AverageRain ← ROUND(TotalRain/365, 4)
// total rainfall in cm to 2dp
TotalRain ← ROUND(TotalRain/10, 2)
// counting the number of days with no rain
NoRain ← 0
FOR Index ← 1 TO 365
IF Rainfall[Index] = 0
THEN
NoRain ← NoRain + 1
ENDIF
NEXT Index
// finding the longest number of consecutive rain free days IF NoRain > 0
THEN
MaxDryDays ← 1
DryDays ← 1
FOR Index ← 1 TO 365-1
IF Rainfall[Index] = 0 AND Rainfall[Index + 1] = 0 THEN
DryDays ← DryDays + 1
IF DryDays > MaxDryDays
THEN
MaxDryDays ← DryDays
ENDIF
ELSE
DryDays ← 1
ENDIF
NEXT Index
ELSE
MaxDryDays ← 0
DryDays ← 0
ENDIF
// outputting the statistics with messages
OUTPUT "The total rainfall for the year was ", TotalRain, " cm" OUTPUT "The average daily rainfall was ", AverageRain, " mm" OUTPUT "The total number of days with no rainfall was ", NoRain, " day(s)"
OUTPUT "The longest period with no rainfall was ", MaxDryDays, " day(s)"
// checking if there was a drought
IF MaxDryDays >= 15
THEN
OUTPUT ""
OUTPUT "There was a drought this year because the longest period with no rainfall was 15 days or longer"
ELSE
OUTPUT ""
OUTPUT "There was no drought this year, because the longest period with no rainfall was shorter than 15 days"
ENDIF
AO2: Apply knowledge and understanding of the principles and concepts of computer science to a given context, including the analysis and design of computational or programming problems
1–3
4–6
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