What is "single responsibility principle"

n. (context programming object-oriented English) Principle that states that every class should have a single responsibility entirely encapsulated by that class.

The single responsibility principle states that every module or class should have responsibility over a single part of the functionality provided by the software, and that responsibility should be entirely encapsulated by the class. All its services should be narrowly aligned with that responsibility. Robert C. Martin expresses the principle as follows: