AQA AS Computing 1.4 Algorithm Design

Question 1

Algorithm

Answer 1

A description, independent of any programming language, of a process that achieves some task. It is a step by step procedure for solving a problem.

Question 2

Program

Answer 2

A description in a programming language of a process that achieves some useful result.

Question 3

Sequence

Answer 3

Consecutive steps or groups of steps processed one after another in the order that they arise

Question 4

Selection

Answer 4

a decision making step (If… then… else…/case)

Question 5

Iteration (aka repetition)

Answer 5

A step, or sequence of steps that are repeated until some condition is satisfied. Repeat… Until…/ While… Do…/ For…

Question 6

4 stages of algorithm design

Answer 6

1. Identify the problem inputs
2. Identify the problem outputs
3. Determine the variables
4. Derive an algorithm that transforms the inputs into outputs

Question 7

Assignment

Answer 7

An operation that assigns a value into a variable (“:=” in Delphi! You might sometimes see <- or = used)

Question 8

Structured English

Answer 8

A very restricted subset of the English language (resembling a program) E.g..
MULTIPLY hours by pay-rate to get total-pay
INPUT pay-rate
PRINT payslip
etc.

Question 9

Pseudocode

Answer 9

Code that resembles a programming language but that uses less strict syntax to express an algorithm and is independent of any real programming language

Question 10

Hand trace, desk check or dry run

Answer 10

a careful, step-by-step simulation on paper of how an algorithm would be executed by a computer