Computer Science IB SL Definitions OOP

Method

A behaviour/procedure used by an object as specified within the object class.

Inheritance

A mechanism by which one class acquires the properties (data fields and methods) of another class.

Instance variable

A member of a class which defines the state of the class (e.g. AnimalName) as opposed to the behaviours of a class (e.g. countMoney). They have primitive (e.g. integer, float) or non-primitive (e.g. String) data types.

Constructor

A method with the same name as the class that initialises the values of the instance variables of an object of the class which has been instantiated.

Return value

A value which is the end product of a method which was executed.

Local variable

A variable that is defined and is capable of being used only in one specified program block.

Parameter variable

A variable which is used as a parameter of a method.

Object-oriented Programming (OOP)

An approach to programming in which units of data are viewed as active objects rather than the passive units envisioned by the procedural paradigm.

Object

An object is a combination of data and the operations that can be performed in association with that data. Each data part of an object is referred to as a data member while the operations can be referred to as methods. The current state of an object is stored in its data members and that state should only be changed or accessed through the methods.

Class

Combination of data and operations that can be performed on that data; specification of the data members and methods of the object.

Static

Expression saying that a method can be used without instantiation of an object.

Primitive

Integer, real, character or Boolean data types.

Public

Members of a class that are accessible from anywhere and from any class.

Private

Members of a class that are only accessible from methods inside the class.

Mutator

Method to set a value of a private field.

Accessor

Methods that return information only and do not alter the state or attributes of an object (getters).

Protected

Modifier which makes a method accessible by methods in the same class, package and by object references that are of at least the same type as the method.

Modularity

One aspect of structured programming in which individual tasks are programmed as distinct sections or modules. One advantage is the ease with which individual sections can be modified without reference to other sections.

Polymorphism

The ability of having duplicate method names and to apply the method that is appropriate for the object to which the method is applied.

Definition

The action of determining the data type and nature of any object created e.g. defining an array of size 10 and type int.

Encapsulation

The combination of data and the operations that act on the data to form a single program unit called an "object".

Instantiation

The creation of a real object from an abstract class.

Extends

The expression used to inherit methods and variables from another class.

Identifier

The name or label chosen by the programmer to represent a variable, method, class, data type or any other element defined within the program.

UML

Unified Modeling Language is a general-purpose modeling language in the field of software engineering, which is designed to provide a standard way to visualize the design of a system.

Signature

the name of a method plus its parameter list (number, type and order).