9618/42 · May/June 2025
Download PDFA program reads data from a text file and stores it in a stack. The stack Stack is stored as a 1D array of up to 20 elements. The pointer TopOfStack stores the index of the last element stored in the stack.
Stack is a global array of strings with all elements initialised to "-1" TopOfStack is a global variable initialised to –1 Write program code to declare and initialise Stack and TopOfStack Save your program as Question1_J25. Copy and paste the program code into part 1(a) in the evidence document.
The function Push() takes a string parameter and attempts to store it on the stack. The function returns –1 if the stack is full. The function returns 1 if the parameter is successfully pushed onto the stack. Write program code for Push() Save your program. Copy and paste the program code into part 1(b) in the evidence document.
The function Pop() returns the next item from the stack. The function returns "–1" if the stack is empty. Write program code for Pop() Save your program. Copy and paste the program code into part 1(c) in the evidence document.
The text file StackData.txt stores numbers and mathematical operators. Each number and operator are on a new line in the text file. The mathematical operators used in this program are:
| mathematical operator | meaning |
|---|---|
| + | addition |
| – | subtraction |
| / | division |
| * | multiplication |
| ^ | power of |
The procedure ReadData(): • takes a string filename as a parameter • opens the file and reads in each line of data • uses the Push() function to insert each line of data onto the stack • outputs "Stack full" if any data cannot be stored on the stack because the stack is full • uses exception handling when opening and reading from the text file. The procedure needs to work for a file that contains an unknown number of lines. Write program code for ReadData() Save your program. Copy and paste the program code into part 1(d) in the evidence document.
The values stored in the stack are used to perform mathematical operations. A total is initialised to the first value in the stack. The first value in the stack will always be a number. The next value will be a mathematical operator and the next value will be the number to apply to the calculation. This is repeated until there are no values left in the stack. There will always be a number following a mathematical operator. For example, the contents of a stack are:
| 10 |
| + |
| 3 |
| – |
| 2 |
TopOfStack The total is initialised to the first value in the stack: 10 total = 10 The next two values are: + 3 total = 10 + 3 = 13 The next two values are: – 2 total = 13 – 2 = 11 The final total is 11 and this is returned. Write program code for the function Calculate() to: • take each value from the stack • calculate and return the final total. Save your program. Copy and paste the program code into part 1(e) in the evidence document.
Write program code to extend the main program to: • take a filename as input from the user • call ReadData() with the input filename • call Calculate() • output the final total. Save your program. Copy and paste the program code into part 1(f)(i) in the evidence document.
Test your program twice with the file names: StackData.txt SecondStack.txt Take a screenshot of the output(s). Save your program. Copy and paste the screenshot into part 1(f)(ii) in the evidence document.
A program stores data in a 1D array of records, HashTable. The array has space for 200 records. Each data item is stored in a specific index of the array that is calculated using an algorithm. The index is calculated from the key field using the formula: Key MOD 200 If two key fields generate the same index, there is a collision. Any records that have a collision are stored in a second array, Spare. This array has space for 100 records. When a collision is detected, the record is stored in the next free space in Spare.
The pseudocode record format is: TYPE NewRecord DECLARE Key : INTEGER DECLARE Item1 : INTEGER DECLARE Item2 : INTEGER ENDTYPE Write program code to declare the record type NewRecord If your chosen programming language does not support record formats, a class can be used instead. Save your program as Question2_J25. Copy and paste the program code into part 2(a) in the evidence document.
Write program code to declare the global arrays HashTable and Spare Save your program. Copy and paste the program code into part 2(b)(i) in the evidence document.
An empty record has the integer –1 stored in each field. The procedure Initialise() stores an empty record in each element in HashTable and Spare Write program code for Initialise() Save your program. Copy and paste the program code into part 2(b)(ii) in the evidence document.
The hash value is calculated from the key field using the formula: Key MOD 200 The function CalculateHash() takes a key field as a parameter and calculates and returns the hash value for the key field. Write program code for CalculateHash() Save your program. Copy and paste the program code into part 2(c) in the evidence document.
The procedure InsertIntoHash(): • takes a record of type NewRecord as a parameter • uses CalculateHash() to calculate the hash value for the key field in the record • checks if the hash value index in HashTable currently stores an empty record ○ if the index stores an empty record, store the parameter in this index ○ if the index does not store an empty record, store the parameter in Spare You can assume there will always be enough space in Spare to store any collisions. Write program code for InsertIntoHash() Save your program. Copy and paste the program code into part 2(d) in the evidence document.
The text file HashData.txt stores up to 200 rows of data to be stored into the hash table. Each row contains three integer numbers separated by commas. The first number is the key field, the second number is item 1 and the third number is item 2. For example: The first row in the text file contains: 646, 12, 568 The key field is 646, item 1 is 12 and item 2 is 568 The procedure CreateHashTable(): • opens the file HashData.txt • creates a record for each row of data in the file • calls InsertIntoHash() with each record. Write program code for CreateHashTable() Save your program. Copy and paste the program code into part 2(e) in the evidence document.
The procedure PrintSpare() outputs the key field of each element in the array Spare that does not contain an empty record. Write program code for PrintSpare() Save your program. Copy and paste the program code into part 2(f)(i) in the evidence document.
The main program should call the procedure to initialise the arrays, call the procedure to create the hash table and then call the procedure to output the contents of the array Spare Write program code for the main program. Save your program. Copy and paste the program code into part 2(f)(ii) in the evidence document.
Test your program. Take a screenshot of the output(s). Save your program. Copy and paste the screenshot into part 2(f)(iii) in the evidence document.
A program stores data about animals using Object-Oriented Programming (OOP). The class Animal stores the data about animals.
| Animal | |
|---|---|
| Name : String | stores the name of the animal |
| Sound : String | stores the sound the animal makes |
| Size : Integer | stores the size of the animal as an integer between 1 (smallest) and 10 (largest) |
| Intelligence : Integer | stores the intelligence of the animal as an integer between 1 (least) and 10 (most) |
| Constructor() | initialises all attributes to its parameter values |
| Description() | returns a string message that contains the data from the attributes |
Write program code to declare the class Animal and its constructor. Do not declare the other methods. Use your programming language appropriate constructor. If you are writing in Python, include attribute declarations using comments. Save your program as Question3_J25. Copy and paste the program code into part 3(a)(i) in the evidence document.
The method Description() creates and returns a string of the animal’s data in the format: "The animal's name is " <Name> ", it makes a " <Sound> ", its size is " <Size> " and its intelligence level is " <Intelligence> For example: The animal's name is Teddy, it makes a Bark, its size is 4 and its intelligence level is 6 Write program code for Description() Save your program. Copy and paste the program code into part 3(a)(ii) in the evidence document.
The class Parrot inherits from the class Animal Parrot inherits the attributes from Animal and overrides the Description() method. The additional attributes and methods in the class Parrot are:
| Parrot | |
|---|---|
| WingSpan : Integer | the width of the parrot's wings to the nearest cm |
| NumberWords : Integer | the number of words the parrot can speak |
| Constructor() | calls the parent constructor using its parameter values; initialises WingSpan and NumberWords to its parameter values |
| ChangeNumberWords() | takes an integer parameter and adds this to the number currently in NumberWords |
Write program code to declare the class Parrot, its constructor and the method ChangeNumberWords() Use your programming language appropriate constructor. If you are writing in Python, include attribute declarations using comments. Save your program. Copy and paste the program code into part 3(b)(i) in the evidence document.
The method Description() in the class Parrot creates and returns a string of the animal’s data in the format: "The animal's name is " <Name> ", it makes a " <Sound> ", its size is " <Size> " and its intelligence level is " <Intelligence> ". It has a wingspan of " <WingSpan> "cm and can say " <NumberWords> " words." For example: The animal's name is Chewie, it makes a Squawk, its size is 1 and its intelligence level is 10. It has a wingspan of 30cm and can say 29 words. Write program code for Description() Save your program. Copy and paste the program code into part 3(b)(ii) in the evidence document.
The class Wolf inherits from the class Animal Wolf inherits the attributes from Animal and overrides the Description() method. The additional attributes and methods in the class Wolf are:
| Wolf | |
|---|---|
| TerritorySize : Integer | stores the size of the area where the wolf lives, to the nearest square mile |
| Constructor() | calls the parent constructor using its parameter values; initialises TerritorySize to its parameter value |
| SetTerritorySize() | takes an integer parameter and adds this to the number currently in TerritorySize |
Write program code to declare the class Wolf, its constructor and the method SetTerritorySize() Use your programming language appropriate constructor. If you are writing in Python, include attribute declarations using comments. Save your program. Copy and paste the program code into part 3(c)(i) in the evidence document.
The method Description() in the class Wolf creates and returns a string of the animal’s data in the format: "The animal's name is " <Name> ", it makes a " <Sound> ", its size is " <Size> " and its intelligence level is " <Intelligence> ". Its territory is " <TerritorySize> " square miles." For example: The animal's name is Nighteyes, it makes a Howl, its size is 8 and its intelligence level is 7. Its territory is 100 square miles. Write program code for Description() Save your program. Copy and paste the program code into part 3(c)(ii) in the evidence document.
The main program declares instances of the classes for three animals: • A parrot with the name ‘Chewie’; it makes a ‘Squawk’ sound. Its size is 1, intelligence is 10, wingspan is 30cm and it can say 29 words. • A wolf with the name ‘Nighteyes’; it makes a ‘Howl’ sound. Its size is 8, intelligence is 7 and its territory is 100 square miles. • An animal that is a horse with the name ‘Copper’; it makes a ‘Neigh’ sound. Its size is 10 and its intelligence is 6. Write program code for the main program. Save your program. Copy and paste the program code into part 3(d)(i) in the evidence document.
The main program also needs to: • decrease the territory for the wolf Nighteyes by 20 square miles • increase the number of words the parrot Chewie can say by 2 words • output the description for all three animals. Write program code to extend the main program. Save your program. Copy and paste the program code into part 3(d)(ii) in the evidence document.
Test your program. Take a screenshot of the output(s). Save your program. Copy and paste the screenshot into part 3(d)(iii) in the evidence document.