What's the difference between abstraction and encapsulation?

Question

In interviews I have been asked to explain the difference between abstraction and encapsulation. My answer has been along the lines of

• Abstraction<

Answer 1

As far as iOS is concerned, it can be said that Objective C files (i.e. .h and .m) use abstraction as well as encapsulation.

Abstraction

Header file (.h) only exposes the functions and public members to outside world. No one knows how they are used unless they have the implementation file with them. It is the .m file that holds all the usage and implementation logic with it self. "Implementation remains unexposed".

Encapsulation

The property (@property) encapsulates the memory management attribute (atomic, strong, retain, weak) of an iVar.