What is the difference between public, private, and protected?

ou use:

• public scope to make that property/method available from anywhere, other classes and instances of the object.

• private scope when you want your property/method to be visible in its own class only.

• protected scope when you want to make your property/method visible in all classes that extend current class including the parent class.

If you don't use any visibility modifier, the property / method will be public.

More: (For comprehensive information)

• PHP Manual - Visibility