What are the differences between "private", "public", and "protected methods"?

ruby access-specifier public-method
Billjk picture Billjk · Mar 27, 2012 · Viewed 26k times · Source

I'm learning Ruby, and have come up to a point where I am confused.

The book I am using is talking about private, public, and protected methods, but I am still a bit confused. What are the differences between each?

Answer

Julio Marins picture Julio Marins · Feb 5, 2014

Public - can be called from anywhere

Private - The method cannot be called outside class scope. The object can only send the message to itself

ex: the baker has bake method as public but break_eggs is private

Protected - You can call an object's protected methods as long as the default object self is an instance of the same class as the object whose method you're calling

ex: with n protected method, c1 can ask c2 to execute c2.n, because c1 and c2 are both instances of the same class

And last but not least:

  • Inheritance: Subclasses inherit the method-access rules of their superclass

if "class D < C", then D will exhibit the same access behaviour as instances of C

reference: http://www.amazon.com/Ruby-Rails-Techniques-Developers/dp/1932394699

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