Varieties of @interface declarations, some with parentheses

Question

I\'ve noticed a variety of @interface declarations for Objective-c classes. I\'d like to understand why developers declare @interface in the follo

Answer 1

What ever goes in the .m file is private. the parens are for categories so you can segment your code into categories to make it more readable. because the code is in .m and private, they called the category Private.