Aqa A-Level Computer Science Key Words

Front 1

Memory

Back 1

The location where instructions and data are stored on the computer

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Algorithm

Back 2

A sequence of steps that can be followed to complete a task that always terminates

Front 3

Syntax

Back 3

The rules of how words are used within a given language

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Memory Address

Back 4

A specific location in memory where instructions or data are stored

Front 5

Assignment

Back 5

The process of giving a value to a variable or constant

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Constant

Back 6

An item of data who's value does not change

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Variable

Back 7

An item of data whose value could change while the program is being run

Front 8

Debug

Back 8

The process of finding and correcting errors in programs

Front 9

Declararion

Back 9

The process of defining variables and constants in terms of their name and data type

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Data type

Back 10

Determines what sort of data are being stored and how it will be handled by the program

Front 11

Integer

Back 11

Any whole positive or negative number including 0

Front 12

Pointer

Back 12

A data item that identifies a particular element in a data structure - normally the front or rear

Front 13

Array

Back 13

A set of related data items sorted under a single identifier. Can work on one or more dimensions

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Element

Back 14

A single value within a set or list - also called a member

Front 15

Record

Back 15

One line of a text file

Front 16

Selection

Back 16

The principle of choosing what action to take based on certain criteria

Front 17

Nesting

Back 17

Placing one set of instructions within another set of instructions

Front 18

Iteration

Back 18

The principle of repeating processes

Front 19

Definite iteration

Back 19

A process that repeats a set number of times

Front 20

Indefinite iteration

Back 20

A process that repeats until a certain condition is met

Front 21

Loop

Back 21

A repeated process

Front 22

Sequence

Back 22

The principle of putting the correct instructions in the right order within a program

Front 23

Arithmetic operation

Back 23

Common expressions such as +, -, /, x

Front 24

Rounding

Back 24

Reducing the number of digits used to represent a number while maintaining a value that is approximately equivalent

Front 25

Truncating.

Back 25

The process of cutting off a number after a certain number or characters or decimal places

Front 26

Random number generation

Back 26

A function that produces a completely random number

Front 27

Pseudo-randdom number generator

Back 27

Common in programming languages, a function that produces a random number that is not 100% random

Front 28

Relation operations

Back 28

Expressions that compare two values such as equal to or greater than

Front 29

Boolean operations

Back 29

Expressions that result in a TRUE or FALSE value

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AND

Back 30

Boolean operation that outputs true if both inputs are true

Front 31

OR

Back 31

Boolean operation that outputs true if either of its inputs are true

Front 32

NOT

Back 32

Boolean operation that inverts the result so true becomes false and false becomes true

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XOR

Back 33

Boolean operation that is true if either input is true but not if both inputs are true

Front 34

Character code

Back 34

A binary representation of a particular letter, number or special character

Front 35

Procedural programming languages

Back 35

Languages where the programmer specifies the steps carried out in order to achieve a result

Front 36

Imperative programming languages

Back 36

Languages based on giving the computer commands or procedures to follow

Front 37

Hierarchy chart

Back 37

A diagram that shows the design of a system from the top down

Front 38

Structure chart

Back 38

Similar to a hierarchy chart with the addition of showing how data is passed around the system

Front 39

Top-down approach

Back 39

When designing systems it means that you start at the top of the process and work your way down into smaller and smaller subprocesses

Front 40

Flowchart

Back 40

A digram using standard symbols that describes a process or system

Front 41

System flowchart

Back 41

A diagram that shows individual processes within a system

Front 42

Psudo-code

Back 42

A method of writing code that does not require knowledge of a particular programming language

Front 43

Number Base

Back 43

The number of digits available within a particular number system, e.g. base 10 for decimal, base 2 for binary

Front 44

Bit

Back 44

A single binary digit from a binary number - either a zero or a one

Front 45

Byte

Back 45

A group of bits, typically 8, used to represent a single character

Front 46

Unit

Back 46

The grouping together of bits or bytes to form larger blocks of measurement, e.g. GB, MB

Front 47

Unassigned Binary

Back 47

Binary that represents positive numbers only

Front 48

Two's Complement

Back 48

A method of working with signed binary values

Front 49

Fixed Points

Back 49

Where the decimal/binary point is fixed within a number

Front 50

Floating Point

Back 50

Where the decimal/binary point can move within a number

Front 51

Signed Binary

Back 51

Binary with a positive or negative sign

Front 52

Overflow

Back 52

When a number is too large to be represented with the number of bits allocated

Front 53

Underflow

Back 53

When a number is too small to be represented with the number of bits allowed

Front 54

Normalisation

Back 54

A process for adjusting numbers onto a common scale

Front 55

Precision

Back 55

How accurate a number is

Front 56

Mantisa

Back 56

The significant digits that make up a number

Front 57

Exponant

Back 57

The 'power of' part of a number indicating how far a binary point should be shifted left or right