View source for Object-Oriented Programming

=Internal=

* [[Programming_Languages_Concepts#Object-Oriented_Programming|Programming Languages Concepts]]
* [[Actor Model#Overview|Actor Model]]
* [[UML]]
* [[Go Language Object Oriented Programming|Object-Oriented Programming in Go]]

=Overview=
Object-oriented programming is first and foremost about message passing between [[#Class|class]] [[#Instances|instances]].
=Object-Oriented Analysis and Design=
In software development, design is often assumed to happen '''before''' programming. In reality, analysis, programming and design ten to overlay, combine and interweave. '''Object-oriented analysis''' is the process of looking at a problem, system or task, with the intention of creating an application that addresses it, and identifying the objects and interactions between objects. The analysis stage is about '''what''' needs to be done.

The output of the analysis stage is a set of '''requirements'''.

'''Object-oriented design (OOD)''' is the process of converting the requirements into an '''implementation specification'''. The designer names the objects, defines their behaviors and formally specifies which objects can activate specific behaviors on other objects. This stage is about '''how''' things should be done.

The output of the design stage is the implementation specification.

In most cases, all these stages overlap and the development happens in an iterative model, in which a small part of the project is modeled, designed and programmed, and then the program is iteratively reviewed and expanded.

=Object-Oriented Programming vs Functional Programming=

{{Internal|Object-Oriented Programming vs Functional Programming|Object-Oriented Programming vs Functional Programming}}
=Encapsulation=

Encapsulation is grouping together data and functions that are related to each other. The formal definition of such a bundle of data and functions is a type or a [[#Class|class]].

=Class=

A class represents a type, or a kind, of thing and concept. Classes [[#Encapsulation|encapsulate]] '''state''' - what kind of information, or attributes they can store. Classes also define '''behavior''', or methods. Classes are blueprints for [[#Object|objects]].

=Objects=

An object is a specific instance of a [[#Class|class]].

=Inheritance=

The inheritance implies that there are classes that are very generic, and other classes that are specific. The specific classes can inherit specific attributes and behavior from generic classes, and they can also have specific attributes and behaviors that are particular to them, and to no one else. Thus, classes form hierarchies.

Parent types are called superclasses. Subtypes are called subclasses.

The motivation behind inheritance is code reusability. If something that is generally applicable to a set of classes, that belongs into the superclass, which can be then inherited.

=Polymorphism=