OCR GCSE Computer Science - Algorithms (Paper 2)

Computational Thinking

The thought processes involved in formulating a problem and expressing its solution

Algorithm

A Set of instructions for solving a problem or completing a task

Abstraction

Removing unnecessary detail from a problem to focus on the essentials

Decomposition

Breaking down a large problem into smaller sub-problems and then breaking these down further into small, manageable tasks

Binary Search

Search a sorted array by repeatedly dividing the search interval in half.

Linear Search

Items are examined in sequence

Bubble Sort

Each item in a list is compared to the one next to it, and if it is greater, they swap places

Insertion Sort

One item is taken from the list and placed in the correct position, this is repeated until the list is sorted

Merge Sort

Unsorted list is divided into n sublists, of one element each, two sublists at a time are repeatedly merged until there is one (sorted) list

Exponent

Symbol: ^

Modulo

Another word for remainder, symbol: MOD

Integer Division

Symbol: DIV

Variable

A location in memory in which you can temporarily store text or numbers

Input or Output

Parallelogram in a flowchart

Calculation or Assignment

Rectangle in a flowchart

Start or End

Rounded rectangle in a flowchart

Decision

Diamond in a flowchart

Integer

A whole number

Real

A number with a decimal point

Boolean

Can only be TRUE or FALSE

Character

A single alphabetical or numeric character

String

One or more characters enclosed in quotation marks

Not Equal To

Symbol: <> or !=

Sequence

The statements are executed in the order they are written

Selection

Also known as a decision (IF/ELSE)

Iteration

Repetition (WHILE/FOR/DO)

Switch/Case

A statement used if there are several possible options to be tested

Pseudocode

A kind of structured English for developing algorithms

FOR

A loop is executed a certain number of times

WHILE

The loop is executed while a certain condition is true

DO

The loop is executed until a certain condition is true

Trace Table

Used to determine the output of a program, to find any errors and to determine its purpose