Paper 2: Computational thinking, algorithms and programming

Define abstraction and give an example of its use in a map app.

Explain how decomposition helps when designing a large program.

Trace the algorithm for the input 5 and state the output.

num = input("Enter number")result = 1for i = 1 to num    if i MOD 2 == 0 then        result = result * i    endifnext iprint(result)

Show the stages of a binary search for 'Fig' in [Apple, Banana, Cherry, Date, Elder, Fig, Grape].

Show the list [6, 2, 9, 4] after each pass of an insertion sort.

Describe how a merge sort works.

State the most appropriate data type for: a postcode; the number of pupils in a class; the price of a ticket; whether a ticket is paid for.

Explain what casting is and give an example.

word = "Computer". Using OCR Exam Reference Language, state the output of: print(word.length); print(word.substring(3, 3)); print(word.upper).

State the values of 17 MOD 5 and 17 DIV 5.

A table Books has fields Title, Author, Year and Copies. Write an SQL query to show the title and author of books published after 2015.

seats is a 2D array of 10 rows and 20 columns storing True if a seat is booked. Write a statement to book the seat in row 3, column 7, and one to output whether row 0, column 0 is booked.

Write a statement that stores a random integer from 1 to 100 in a variable called guess.

Describe three ways to make a program more maintainable.

A program accepts a quantity from 1 to 10 inclusive. Complete a test plan with one test each for normal, boundary, invalid and erroneous data, and the expected outcome.

Explain the difference between iterative and final testing.

Complete the truth table for P = (A AND B) OR (NOT A AND C) for the inputs A, B, C = 000, 001, 011, 100, 110, 111.

Name the logic gate that outputs 1 only when both inputs are 1.

Describe two features of an IDE that help programmers find errors.

Section B (answer in OCR Exam Reference Language or a high-level language). A car park charges £2.50 per hour, with a maximum of £12 per day. Blue-badge holders park free. Identify two inputs the program will need.

Write a function charge(hours, badge) that returns the parking charge.

Give the expected return value of charge for: 3 hours, no badge; 6 hours, no badge; 2 hours, badge; and state why the second test is useful.

The array times stores the 100 m times (seconds) of 8 runners: [13.2, 12.8, 14.1, 12.5, 13.9, 12.9, 15.0, 13.4]. Write code to output the number of runners with a time under 13.0 seconds.

Write a procedure that outputs the fastest time and the position (index) in the array of that runner.

Write a program that asks for each runner's name and time for 8 runners, validates that each time is between 9.0 and 30.0, stores them in two arrays, and outputs the names of runners whose time is below the mean time, followed by the mean to 2 decimal places.