IT - definitions

procedural paradigm

an approach to developing a solution where the program operates on data and is organised in self-contained blocks called procedures

object-oriented programming

an approach to developing a solution where the focus is on data rather than processes

methods

the behaviours that an object can preform

object

a self-contained element that contains the properties and methods needed to access and manipulate data values

properties

contain code that facilitates reading and writing to the data within an object

inheritance

enables the properties of one class to be copied to another so that the only differences between the classes need to be reprogrammed

encapsulation

hides an objects data so that it can only be directly accessed by methods within the object

software development environment

software that provides programmers with an integrated set of programming tools to build an application from coding through to testing

syntax errors

an error in the code entered into the code editor e.g. misspelling

machine code

instructions in binary format that can be executed directly by the computer

source code

the original program code written by the programmer

ASCII code

American Standard Code for Information Interchange used to represent characters in 7 or 8 bit

7-bit ASCII code

uses 7-bits to represent each character

8-bit ASCII code

known as the extended ASCII table, uses 8-bits to represent each character

Unicode

a standard for encoding characters, which typically uses 16 bits

hexadecimal

a numbering system that uses base 16

one’s complement

can be used to represent a binary number, when using one’s complement , each bit is inverted

two’s complement

a method of representing signed numbers in a computer

overflow

occurs when the magnitude of the number is greater than the maximum number that can be represented by the computer

decomposition

breaking complex problem down into smaller more manageable problems called sub-problems

pattern recognition

identifying pattern trends in data

abstraction

filtering out details about the problem that will not be required for the solution

algorithm

a set of step-by-step instructions representing the solution to a problem

flowchart

a graphical representation that includes special symbols and flow lines to represent the solution to a problem

Pseudo-code

a set of English-like, language-independent instructions that uses keywords and control structures to represent the solution to a problem

bubble sort

a simple sort method that repeatedly steps through a list of data items; adjacent elements are compared and swapped if they are in the wrong order

insertion sort

a simple sorting algorithm that builds a sorted sub-list one item at a time; the sub-list becomes the new sorted list

linear search

a simple search algorithm that compares every data item in a list to the target value

binary search

a search algorithm that works on a sorted list of data items - the target value is located by finding the mid-point location in the list and comparing that value to the target value

refining a solution

the process of reviewing the design for a solution and making necessary changes so that the design meets the user’s requirements efficiently and accurately

Data requirements

the data that a program or system uses, including data input, information output and any values to be stored temporarily during processing

user interface

any part of a system that the user can interact with; this includes data capture forms, menus and buttons

Dry run

a paper-based exercise that allows the programmer to go through the solution step by step; the dry run will highlight any errors in the logic of the solution

variable

a data value stored in memory that can change during program execution

selection

where only some lines of code need to be run and only if a certain condition is met

iteration

The use of loops and conditions to repeat sections of codes

Data validation

carried out by a computer automatically when data is input; it ensures that data is reasonable, sensible and within acceptable limits

Presence check

used to ensure that the user has entered data and has not left a value or field blank

length check

used to ensure that the user has entered data that does not exceed or is not shorter than a particular number of characters

Type check

Used to ensure that data entered is of the correct data type

format check

used to ensure that data entered is in the correct format; this means that data must conform to a pattern

Test case

a document that contains a set of tests to help the programmer verify that code works as expected

White box testing

a method of testing which examines the underlying structure of the application or code which has been developed

black box testing

where the tester is unaware of the internal structure of the application they are testing

unit testing

testing one module or unit of code to ensure that it is working as expected

Integration testing

when a number of units have been tested they are combined together to form a sub-system. Integration testing ensure that all of the units work together correctly

System testing

carried out on a complete and fully integrated system to ensure correct outputs are produced in compliance with the user requirements

Extreme data

used to test that the system can cope with very small or vary large data values

valid data

used to test that the system operates as expected with normal data

invalid data

used to test that the system can process invalid data and does not crash when invalid data is entered

Null data

used to test that the system can cope when no data is entered

user requrements

a document that details what the end user expects the system to do

Robustness

a measure of the system’s ability to continue to run when high volumes of valid, exceptional or invalid data are entered

function

a procedure written to carry out a specific task