Object Oriented Concepts Every Dummy Must Know

Abstraction

• Abstraction is Only showing what is necessary and encapsulating (hiding) unnecessary parts. 
• If you take a car you interact with it using abstractions 
• you use gas pedal, steering wheel which hides internal details
• It is keeping a clear separation between abstract properties of a data type and the concrete details of its implementation. 
• It is not presenting the details but only show the parts which are necessary.  
• Hiding implementation 

To abstract properties we can use private modifier. Abstraction is hiding implementation details using abstract classes and interfaces.

http://stackoverflow.com/questions/2918308/explaining-abstraction-to-a-non-programmer

http://stackoverflow.com/questions/16938667/how-abstraction-and-encapsulation-differ

http://www.introprogramming.info/english-intro-csharp-book/read-online/chapter-20-object-oriented-programming-principles/#_Toc362296567 

Encapsulation : 

• Hiding state/data. Information hiding mechanism
• It is the opposite of Abstraction.  

http://stackoverflow.com/questions/24626/abstraction-vs-information-hiding-vs-encapsulation
https://www.google.com/search?q=encapsulation+vs+abstraction&ie=utf-8&oe=utf-8
http://stackoverflow.com/questions/742341/difference-between-abstraction-and-encapsulation

Composition : Combining simple types to make a complex type (Car composed of Wheels, Body etc.). An object of a composite type "has an" object of a simple type.

http://en.wikipedia.org/wiki/Object_composition

Aggregation : (See composition vs aggregation - adobe)

Is a form of object composition.

https://atomicobject.com/resources/oo-programming/object-oriented-aggregation

Inheritance : When an object or class based on another object or class. 

Inheritance is "is a" relationship while, composition is "has a" relationship

Articles

https://mydevelopedworld.wordpress.com/2012/07/25/object-oriented-programming-inheritance-vs-composition/

• inheritance defined statically at compile time.
• object composition defined dynamically at run time, through objects acquiring references to other objects
• inheritance : reuse by subclassing : white box reuse (internals of parent are visible)
• composition : well defined interfaces: black box reuse (no internal objects are visible)
• 
  

updated: 2014