objective c - @interface, @implementaion sections. When to use vs not use? -

so, beginner, learning program in objective-c. understand concepts of @interface , @implementation sections , why they're there. book using have other examples goes straight @autoreleasepool, find easier grasp conceptually.

i missing key concept of these 2 sections (@interface , @implementation). can me understand when need use these sections define instance variables , methods, versus entering info under @autoreleasepool?

what failing comprehend here?

thanks lot.

@interface , @implementation versus @autoreleasepool used in different contexts. learned, @interface declares class, while @implementation contains implementation of methods. @autoreleasepool used encapsulate block of code , make sure objects autoreleased in block released @ end of @autoreleasepool block. need create own @autoreleasepool blocks. in cases there single pool created you.