Programming Fundamentals Worksheets, Questions and Revision

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GCSE · Computational thinking, algorithms and programming

P2.2 Programming Fundamentals

OCR J277 · Calculators not allowed · about 105 minutes

Total Marks

Name: _______________________________ Date: ____ / ____ / ______

Answer ALL questions. Show all your working.

1

This question is about data types used in programming.

(a)Which data type would be most appropriate to store the answer to the question 'Is the number even?'(1)

A) Integer
B) Boolean
C) String
D) Real

(b)State the most appropriate data type for each value: (i) the number of pets a person owns (ii) the price of a chocolate bar, 2.35 pounds (iii) a student's exam grade letter, for example 'A' (iv) whether a password entered is correct(4)

(c)A programmer stores a UK postcode, for example 'SW1A 1AA', using a Real data type. Explain why this is not appropriate and state a more suitable data type.(2)

(Total for Question 1 is 7 marks)

2

This question is about variables and constants.

(a)A program calculates the area of a circle using the formula area = π * radius². Define the term 'variable' and the term 'constant', giving one example of each from this program.(2)

(b)State two benefits to a programmer of using a named constant, such as PI, instead of writing the literal value 3.14159 directly wherever it is needed in the code.(2)

(Total for Question 2 is 4 marks)

3

Complete the table by evaluating each expression.
17 DIV 5 = ?
17 MOD 5 = ?
2 ^ 3 = ?
(10 - 3) * 2 = ?

(Total for Question 3 is 4 marks)

4

Given the variables x = 7, y = 3 and z = 10, state whether each expression evaluates to True or False.
(i) x > y AND z < y
(ii) NOT (x == y)
(iii) (x + y) ≥ z
(iv) x < y OR z > y

(Total for Question 4 is 4 marks)

5

A program reads a user's age from the keyboard using INPUT, which always stores the value as a String.

(a)Write one line of pseudocode that converts the String stored in ageInput into an integer and stores the result in a variable called age.(1)

(b)Explain why this conversion is necessary before the program can use age in a calculation such as age + 1.(2)

(Total for Question 5 is 3 marks)

6

A program classifies a percentage exam score using the following pseudocode.

INPUT score
IF score >= 90 THEN
  OUTPUT "Distinction"
ELSE IF score >= 70 THEN
  OUTPUT "Merit"
ELSE IF score >= 40 THEN
  OUTPUT "Pass"
ELSE
  OUTPUT "Fail"
ENDIF

(a)Complete the trace table below by stating the output produced for each input score: 95, 68, 40, 39.(4)

(b)State the term used for test data that lies exactly on one of the boundaries in this algorithm, and give one example value from the algorithm that is boundary data.(2)

(Total for Question 6 is 6 marks)

7

A program uses the following pseudocode.

total = 0
FOR i = 1 TO 5
  total = total + i * 2
NEXT i
OUTPUT total

(a)Complete a trace table for this algorithm, showing the value of i and the value of total after each pass through the loop.(5)

(b)State the value output by this algorithm.(1)

(Total for Question 7 is 6 marks)

8

A cafe offers a discount: a student spending more than 15 pounds gets 20% off; a student spending 15 pounds or less gets 10% off; a non-student gets no discount.

Write an algorithm, using nested IF statements in pseudocode, that inputs a Boolean isStudent and a Real spend, then outputs the discount percentage that applies (0, 10 or 20).

(Total for Question 8 is 4 marks)

9

A variable name stores the string "Amelia Khan".

(a)State the value returned by each of the following: (i) LENGTH(name) (ii) SUBSTRING(0, 6, name) (iii) UCASE(name)(3)

(b)Write one line of pseudocode that outputs just the first character of name.(1)

(c)Write a line of pseudocode that joins the title "Ms " to the front of name and stores the result in a new variable called fullName.(2)

(Total for Question 9 is 6 marks)

10

Write pseudocode that opens a text file called 'players.txt' for reading, reads every line in the file one at a time until the end of the file is reached, outputs each line, then closes the file.

(Total for Question 10 is 5 marks)

11

A sports club keeps a database table Members(MemberID, FirstName, Surname, Town, JoinYear).

Write an SQL query that selects the FirstName and Surname of every member from the town 'Leeds', ordered alphabetically by Surname.

(Total for Question 11 is 4 marks)

12

Write an algorithm, using pseudocode, that repeatedly asks the user to input an integer age. The algorithm must use a WHILE loop to reject any value that is not between 0 and 120 inclusive, printing an error message and asking again, and must only continue once a valid age has been entered.

(Total for Question 12 is 5 marks)

13

An array temps stores 6 daily temperatures, in degrees Celsius, recorded in Cambridge: [14, 9, 17, 20, 11, 8].

Write an algorithm using a FOR loop that calculates and outputs the mean of the values in temps.

(Total for Question 13 is 6 marks)

14

Using the same Members table from Question 11, write an SQL query that counts how many members joined in the year 2020.

(Total for Question 14 is 3 marks)

15

Write a function called findLargest that takes two integer parameters, num1 and num2, and returns whichever value is the larger of the two.

(Total for Question 15 is 5 marks)

16

A procedure declares a variable called total that is used only inside that procedure.

(a)State what is meant by the term 'local variable'.(1)

(b)Identify whether total is a local or global variable, and explain the problem this could cause if another part of the program needs to use the value stored in total after the procedure has finished running.(3)

(Total for Question 16 is 4 marks)

17

A programmer intended the following algorithm to sum only the even numbers from 1 to 10, but it contains a logic error.

total = 0
FOR num = 1 TO 10
  IF num MOD 2 == 1 THEN
    total = total + num
  ENDIF
NEXT num
OUTPUT total

(a)State what this algorithm actually calculates as it is currently written.(1)

(b)Identify the line of pseudocode that contains the logic error.(1)

(c)State the corrected line of pseudocode needed so the algorithm sums only the even numbers.(1)

(d)Using the corrected algorithm, state the value that would be output.(2)

(Total for Question 17 is 5 marks)

18

A game of noughts and crosses stores its board as a 2D array board[0:2, 0:2], where each cell contains "X", "O" or "-" for an empty cell.

Write pseudocode, using nested FOR loops, that searches every cell of board and counts how many cells contain "X", storing the result in a variable called count.

(Total for Question 18 is 6 marks)

19

A large program is currently written as one long sequence of instructions. Discuss the benefits to the programmer of breaking the program down into functions and procedures (subprograms) instead. Refer to code reuse, testing, readability and maintenance in your answer.

(Total for Question 19 is 6 marks)

20

A school records the test scores, out of 100, of 8 students in a computer science class.

Write an algorithm, using pseudocode, that:
- uses a loop to input 8 scores, validating each one so it must be between 0 and 100 inclusive before it is accepted
- stores each valid score in an array called scores
- calculates and outputs the average (mean) score
- outputs 'Well done, class!' if the average is 60 or above, otherwise outputs 'More revision needed'

Your algorithm should make use of iteration, selection and an array.

(Total for Question 20 is 10 marks)

Mark scheme · P2.2 Programming Fundamentals

Question 1

(a) B1 B selected (Boolean) cao
(a) Answer: B
(b) B1 (i) Integer
(b) B1 (ii) Real (accept float) oe
(b) B1 (iii) Character
(b) B1 (iv) Boolean
(b) Answer: (i) Integer (ii) Real (iii) Character (iv) Boolean
(c) B1 reason: a postcode contains letters and spaces / is not used in a calculation, so it cannot be stored as a number oe
(c) B1 correct alternative type stated: String
(c) Answer: A postcode is not purely numeric and is never used in arithmetic, so it should be stored as a String.

Question 2

(a) B1 variable: a named storage location whose value can change while the program runs, e.g. radius
(a) B1 constant: a named storage location whose value stays fixed throughout the program, e.g. π (3.14159)
(a) Answer: Variable: radius (its value changes each time the program runs). Constant: π = 3.14159 (its value never changes).
(b) B1 if the value needs updating it only has to be changed in one place, reducing errors oe
(b) B1 a meaningful name makes the code easier to read and understand oe
(b) Answer: 1. Only one place needs updating if the value changes. 2. A named constant makes the code's purpose clearer to read.

Question 3

B1 17 DIV 5 = 3 cao
B1 17 MOD 5 = 2 cao
B1 2 ^ 3 = 8 cao
B1 (10 - 3) * 2 = 14 cao
Answer: 3, 2, 8, 14

Question 4

B1 (i) False cao
B1 (ii) True cao
B1 (iii) True cao
B1 (iv) True cao
Answer: (i) False (ii) True (iii) True (iv) True

Question 5

(a) M1 age = STRING_TO_INT(ageInput) or equivalent cast, any correct syntax
(a) Answer: age = STRING_TO_INT(ageInput)
(b) B1 INPUT stores the value as a String / text data type
(b) B1 arithmetic operators only work on numeric data types, so the String must be cast to an integer first oe
(b) Answer: Because INPUT always produces a String, and a String cannot be used with + in arithmetic; it must first be cast to an Integer.

Question 6

(a) B1 score 95 -> Distinction cao
(a) B1 score 68 -> Pass cao
(a) B1 score 40 -> Pass cao
(a) B1 score 39 -> Fail cao
(a) Answer: 95 -> Distinction, 68 -> Pass, 40 -> Pass, 39 -> Fail
(b) B1 boundary data (accept borderline data)
(b) B1 any one of 90, 70 or 40 given as an example
(b) Answer: Boundary data, for example 40.

Question 7

(a) B1 i = 1, total = 2 cao
(a) B1 i = 2, total = 6 cao
(a) B1 i = 3, total = 12 cao
(a) B1 i = 4, total = 20 cao
(a) B1 i = 5, total = 30 cao
(a) Answer: i: 1,2,3,4,5 -> total: 2,6,12,20,30
(b) B1 30, follow through from part (a)
(b) Answer: 30

Question 8

M1 outer IF tests isStudent
M1 nested IF inside correctly tests spend > 15 and outputs 20
M1 correct ELSE branch (student, spend ≤ 15) outputs 10
M1 correct final ELSE branch (not a student) outputs 0; any correct logic, ignore minor syntax

Answer:

INPUT isStudent
INPUT spend
IF isStudent == True THEN
  IF spend > 15 THEN
    OUTPUT 20
  ELSE
    OUTPUT 10
  ENDIF
ELSE
  OUTPUT 0
ENDIF

Question 9

(a) B1 (i) 11 cao
(a) B1 (ii) Amelia cao
(a) B1 (iii) AMELIA KHAN cao
(a) Answer: (i) 11 (ii) Amelia (iii) AMELIA KHAN
(b) M1 OUTPUT SUBSTRING(0, 1, name) or equivalent, any correct syntax
(b) Answer: OUTPUT SUBSTRING(0, 1, name)
(c) M1 correct use of concatenation (+) between "Ms " and name
(c) A1 correct assignment to fullName in the correct order
(c) Answer: fullName = "Ms " + name

Question 10

M1 file opened for reading, e.g. file = OPENFILE("players.txt", READ)
M1 loop condition correctly tests for end of file using EOF(file)
M1 a line is read from the file inside the loop using READFILE
M1 each line read is output inside the loop
M1 file closed after the loop using CLOSEFILE(file); any correct logic, ignore minor syntax

Answer:

file = OPENFILE("players.txt", READ)
WHILE NOT EOF(file)
  line = READFILE(file)
  OUTPUT line
ENDWHILE

CLOSEFILE(file)

Question 11

M1 SELECT FirstName, Surname
M1 FROM Members
M1 WHERE Town = 'Leeds'
M1 ORDER BY Surname; any correct logic, ignore case/semicolon
Answer: SELECT FirstName, Surname FROM Members WHERE Town = 'Leeds' ORDER BY Surname;

Question 12

M1 an initial INPUT of age before the loop condition is tested
M1 WHILE condition correctly tests both bounds, e.g. age < 0 OR age > 120
M1 an error message is output inside the loop
M1 age is re-input inside the loop
M1 overall structure correctly repeats until a valid value is entered; any correct logic, ignore minor syntax

Answer:

INPUT age
WHILE age < 0 OR age > 120
  OUTPUT "Invalid age, try again"
  INPUT age
ENDWHILE
OUTPUT "Age accepted"

Question 13

M1 a total variable is declared and initialised to 0 before the loop
M1 a FOR loop correctly iterates across all 6 indices of the array
M1 each element temps[i] is added to total inside the loop
M1 mean is correctly calculated as total divided by 6 after the loop
M1 the mean is output
A1 final value correct: 13.2 (1 dp), cao ft from the algorithm

Answer:

total = 0
FOR i = 0 TO 5
  total = total + temps[i]
NEXT i
mean = total / 6
OUTPUT mean

Question 14

M1 COUNT function used, e.g. COUNT(*) or COUNT(MemberID)
M1 FROM Members
M1 WHERE JoinYear = 2020; any correct logic, ignore semicolon
Answer: SELECT COUNT(*) FROM Members WHERE JoinYear = 2020;

Question 15

M1 correct FUNCTION header with two parameters, e.g. FUNCTION findLargest(num1, num2)
M1 an IF statement correctly compares num1 and num2
M1 correct RETURN of num1 when num1 is larger
M1 correct RETURN of num2 in the ELSE branch
M1 function correctly closed with ENDFUNCTION; any correct logic, ignore minor syntax

Answer:

FUNCTION findLargest(num1, num2)
  IF num1 > num2 THEN
    RETURN num1
  ELSE
    RETURN num2
  ENDIF
ENDFUNCTION

Question 16

(a) B1 a variable that can only be accessed / used within the subprogram (procedure or function) in which it is declared
(a) Answer: A local variable is one that only exists and can be used inside the subprogram in which it was declared.
(b) B1 identifies total as a local variable
(b) B1 explains that total goes out of scope / is deleted once the procedure ends, so its value is lost
(b) B1 states a valid fix, e.g. return the value from a function, pass it as a parameter, or make it global oe
(b) Answer: total is local. Once the procedure ends, total no longer exists, so its value cannot be read elsewhere. This could be fixed by using a function to RETURN the value, or by passing it out via a parameter.

Question 17

(a) B1 the sum of the odd numbers from 1 to 10 (or equivalent description)
(a) Answer: It sums the odd numbers between 1 and 10.
(b) B1 IF num MOD 2 == 1 THEN
(b) Answer: IF num MOD 2 == 1 THEN
(c) B1 IF num MOD 2 == 0 THEN
(c) Answer: IF num MOD 2 == 0 THEN
(d) M1 even numbers 2, 4, 6, 8, 10 identified / added
(d) A1 30 cao, ft from part (c)
(d) Answer: 30

Question 18

M1 count initialised to 0 before the loops
M1 outer FOR loop correctly iterates rows 0 to 2
M1 inner FOR loop correctly nested, iterating columns 0 to 2
M1 IF statement correctly compares board[row, col] to "X"
M1 count incremented by 1 inside the IF
M1 count correctly output after both loops complete; any correct logic, ignore minor syntax

Answer:

count = 0
FOR row = 0 TO 2
  FOR col = 0 TO 2
    IF board[row, col] == "X" THEN
      count = count + 1
    ENDIF
  NEXT col
NEXT row
OUTPUT count

Question 19

Level 1 (1-2): Basic, isolated points about subprograms with little or no reference to the given themes (reuse, testing, readability, maintenance). Little linking of ideas.
Level 2 (3-4): Sound discussion covering two or three relevant benefits, with some explanation of why each matters, but underdeveloped or only loosely linked to programming practice.
Level 3 (5-6): Thorough, well-linked discussion covering multiple benefits (for example reuse, testing, readability, maintenance, division of work) with clear explanation of why each improves the development process, using appropriate technical vocabulary throughout.
Indicative content:
- Code reuse: a subprogram can be called multiple times from different parts of the program (or in other programs), avoiding rewriting the same logic repeatedly.
- Reduces duplication, so there is less code to maintain and less chance of the same bug existing in several places.
- Testing: each subprogram can be tested in isolation before being integrated, making faults easier to locate.
- Readability: splitting a program into clearly named subprograms makes the overall structure easier to follow than one long block of code.
- Maintenance: if a fault is found or a rule changes, it only needs to be corrected once, inside the relevant subprogram, rather than in every place the logic is used.
- Parameters allow subprograms to be flexible and reused with different data.
- Larger projects can be divided between different programmers, who can each work on separate subprograms.
- Abstraction: subprograms hide the detail of how a task is done, so other parts of the program only need to know what the subprogram does, reducing complexity.

Question 20

M1 array scores correctly declared to hold 8 elements
M1 total variable initialised to 0 before the main loop
M1 an outer FOR loop correctly repeats 8 times (once per student)
M1 a score is input inside the loop
M1 a validation loop (WHILE) correctly re-tests the score against both 0 and 100
M1 an error message is output and the score re-input inside the validation loop
M1 the valid score is stored in the correct array element, e.g. scores[i]
M1 each score is added to total, and average is correctly calculated as total / 8 after the main loop
M1 an IF statement correctly compares average to 60
M1 correct outputs matched to each branch: 'Well done, class!' if average ≥ 60, else 'More revision needed'; any correct logic, ignore minor syntax, up to 10 marks total

Answer:

DECLARE scores : ARRAY[0:7] OF INTEGER
total = 0
FOR i = 0 TO 7
  INPUT mark
  WHILE mark < 0 OR mark > 100
    OUTPUT "Invalid, enter again"
    INPUT mark
  ENDWHILE
  scores[i] = mark
  total = total + scores[i]
NEXT i
average = total / 8
OUTPUT average
IF average >= 60 THEN
  OUTPUT "Well done, class!"
ELSE
  OUTPUT "More revision needed"
ENDIF

Programming Fundamentals - Worksheets, Questions and Revision

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