Paper 1: Computational thinking and programming skills

Which one of the following best describes abstraction?

Which data type is most suitable for storing a person's height in metres?

The algorithm below is written in AQA pseudo-code.

total ← 0FOR i ← 1 TO 5  IF i MOD 2 = 1 THEN    total ← total + i  ENDIFENDFOROUTPUT total

State the value of total at the end of each iteration of the FOR loop, and the final output.

State the purpose of the algorithm in 03.1.

Explain why a binary search cannot be used on the list [19, 3, 40, 8, 25].

Show the steps a binary search takes to find 31 in the list [3, 8, 12, 19, 25, 31, 40].

Compare the efficiency of linear search and binary search on a large sorted list.

Show the result of the first pass of a bubble sort (ascending) on the list [7, 3, 9, 1].

Give one advantage and one disadvantage of merge sort compared with bubble sort.

Write a program that asks the user to enter a password and keeps asking until the password is at least 8 characters long. It should then output 'Accepted'. You may use AQA pseudo-code or a high-level language.

The subroutine below calculates the area of a rectangle.

SUBROUTINE area(w, h)  RETURN w * hENDSUBROUTINE

Identify one parameter used in the subroutine.

Explain one advantage of using local variables in subroutines.

Write a subroutine called perimeter that takes the width and height of a rectangle and returns its perimeter.

An array is declared: scores ← [12, 45, 7, 30, 21]. Arrays are indexed from 0. State the value of scores[2].

Write an algorithm that finds the highest value in scores and the index where it is stored, and outputs both.

name ← 'Plasmo'. State the value returned by LEN(name).

In AQA pseudo-code, SUBSTRING(start, end, string) returns characters from position start to end inclusive (from 0). State the value of SUBSTRING(0, 2, name).

Write an algorithm that counts the number of vowels (a, e, i, o, u) in a string entered by the user and outputs the count.

Write code that asks for a mark between 0 and 100 inclusive and repeats the request until a valid mark is entered.

Explain the difference between validation and verification.

Write an authentication routine. The stored username is 'admin' and password is 'Plasm0!'. The user has three attempts; output 'Welcome' if correct or 'Locked' after three failures.

A program accepts ages from 11 to 16 inclusive. Give one example each of normal, boundary and erroneous test data.

Explain the difference between a syntax error and a logic error.

Write a program that simulates rolling two six-sided dice 1,000 times and outputs how many times the total was 7. Use RANDOM_INT(1, 6) for a random integer from 1 to 6.

A 2D array is declared: grid ← [[3, 5, 2], [8, 1, 4]]. State the value of grid[1][2] (row, column, indexed from 0).

Write an algorithm that outputs the total of every value in grid.

A cinema charges £6 for children (under 12), £7 for seniors (65 and over) and £10 for everyone else. Write a program that: asks how many tickets are needed; asks for the age of each person; calculates the total cost; applies a 20% discount if the user says it is Tuesday; outputs the total cost.

Explain what is meant by a structured approach to programming.

Trace the algorithm and state the output.

n ← 13count ← 0WHILE n ≠ 1  IF n MOD 2 = 0 THEN    n ← n DIV 2  ELSE    n ← 3 * n + 1  ENDIF  count ← count + 1ENDWHILEOUTPUT count

x ← 7. State whether (x > 5 AND x < 10) OR x = 0 is True or False.

Write a selection statement that outputs 'Teen' if age is between 13 and 19 inclusive.

Explain why a programmer might use a FOR loop rather than a WHILE loop.

Give two benefits of using subroutines.