A Level Computer Science 9618 Paper 22, May/June 2025

Choice of program development cycle depends on the approach/method required to produce the program OR a factor that would influence the choice of program development cycle (e.g. Rapid development of program/prototypes required, Need for prototypes (at an early stage), Complexity of problem, Skills / experience of development team / programmer(s), Budget / Time / Resources available, Size of development team, Developer / programmer can return to earlier stages / any stage, Avoidance of repeating previous stages in development of program, How much involvement clients will have, Allows the (program) requirements to be changed during program development, (Program) requirements agreed at start of development of program)

Which programming language would best be suited to control the production line // Which programming language would best suit the problem being solved

Change to (production line) requirements

New technology / hardware available (to control production line)

Changes made to library modules used

Change in relevant legislation

Perfective // Corrective

RIGHT(MachineCode, 4): STRING

Speed * 2.5: REAL

NOT Status: BOOLEAN

IS_NUM(Check): BOOLEAN

Two / 2

1000

Correct upper and lower bound: [0:99, 0:9]

All other parts of declaration: DECLARE Product : ARRAY [0:99, 0:9] OF INTEGER

To increase the level of detail of the algorithm // To break the problem / task into smaller steps …

… until steps can be directly translated into lines of code // from which it can be programmed

Hours worked between 1 and 40 inclusive, Sales value <= 2000, Bonus Pay: 0

Hours worked above 40, Sales value <= 2000, Bonus Pay: 10

Hours worked between 1 and 40 inclusive, Sales value > 2000, Bonus Pay: 50

Hours worked above 40, Sales value above 2000, Bonus Pay: 100

Simple modules are written to replace each of the unfinished modules.

Each simple module will return an expected value / will output a message to show it has been called.

Type of error: Logic (error) OR Run-time (error)

Corresponding description: Where the program does not behave as expected / Does not give expected result / An error in the logic of the algorithm (for Logic) OR The program performs an illegal operation (for Run-time)

Declare all variables used

Use RAND() function with any integer parameter

Use INT() function with any numeric parameter

Conditional loop until two different random numbers are generated

Use INT() function using random number generated between -10 and 10 inclusive in a loop

Output two different random integers / numbers

Check if both random integers / numbers are negative

then output a (third) random integer / number between 30 and 35 inclusive

Initialise Index used for Number to either 1 or 0 before first loop

Loop 100 times

Input value

Increment array index and store value in Number array at element referenced by array index in a loop

Output loop starts at last element in Number array

Output Number array element referenced by Index in a loop

Output all elements of Number array once in reverse order

The three new states drawn and labelled.

Two of the events drawn with labels connecting correct states and correct line direction

Four of the events drawn with labels connecting correct states and correct line direction.

All and only six events drawn with labels connecting correct states and correct line direction.

Any Initialisation of count for number of pictures taken each hour // Initialisation of 24 array elements to 0 // Initialisation of 24 Integer variables to 0

Open "TimeTaken.txt" for read and subsequently close

Conditional loop until EOF

Read a line from "TimeTaken.txt" in a loop

Extract Hour from line read in a loop

A mechanism to compare current hour extracted from file with last one read from file in a loop // Convert Hour to an integer value in a loop

If hours same increment count in a loop // Increment appropriate array element / variable in a loop

If not same output count (with a suitable message) and update Hour <- NextHour and set Count to 1 in a loop // Output of each hour and corresponding count variable (with a suitable message) for all values where count is not zero

Region 1: Value=1043, Start=2, Unused=8, New=8, Last=-1, Current=2

Region 2: Last=2, Current=3

Region 3: Last=3, Current=1

Region 4: Last=1, Current=7 and Last=7, Current=4

Global array Data row 8 containing the value 1043

Global array Pointer row 7 containing the value 8 and row 8 containing the value 4

All other rows in both arrays

Identifying the ADT as a linked list

Identifying operation as inserting / adding a value / node into a linked list

Create function header and ending with correct parameter and return type

Check CustomerID is in range / within range and if not return -1

(Conditional) loop iterating through each element in array / FOR Loop / Conditional loop that halves array search space with each iteration

Check for current element in array contains required customer ID in a loop

If found set value to terminate loop / return loyalty points / Mechanism to end loop if CustomerID is found in array in a loop

Terminating loop when customer ID found

Terminating loop when current customer ID is 99999 / Mechanism to end loop if CustomerID is not in array in a loop

Return either loyalty points for the customer found or -1 if not found

Create procedure header and ending

Declare and initialise Index, Sum and Count

Loop through all elements in Loyalty array

… or terminates when column1 of Loyalty array equals 99999 in a loop

Check if loyalty points greater than or equal to 11 in a loop

If true output customer ID

Sum points and Increment Count in a loop

An array can only store data of the same type // An array cannot store data of different types

a new (composite) data type / record is defined (that consists of both INTEGER and STRING) // Converting loyalty points to string and concatenating / joining / append with Customer ID

an array based on this new type is declared // Storing concatenated string in an array of string