Structs and Functions or Classes and Methods?

I have a struct called Circle (it has members x, y, and r). I define it and give a few function declarations in a Circle.h file and define those functions in a Circle.m file.

I did it this way just because that's how CGRects are done.

But then it occurred to me that this is an awful lot like a class. Is there any real reason that I should or shouldn't make this a class? If I shouldn't make this a class, I'm kind of wondering why I should make anything a class.

Thoughts?

 

One con of using a class (in Obj-C):
Struct instances can be placed on the stack or heap. Class instances can only go on the heap.

By extension, I must alloc and init if I'm using a class whereas if I'm using a struct I may not have to - I feel like this might result in some minor performance benefits when using structs. Currently, in my code using my circles, I haven't had to call alloc or malloc or calloc or any other memory function yet.

I have thought of a few things that classes offer out of the box that I couldn't trivially replicate with structs (like delegation,) but I still haven't yet thought of a reason to make my circles be instances of a class instead of a struct.

 

I have a C array + an int tracking the size of the array. Order of the circles doesn't matter so inserts and deletes are pretty easy (swap the object you want to remove with the last one, reduce the int tracking the size... Inserts just always go at the end.)

Oh, I just realized why you're asking - NSArrays only hold NSObjects.