title: Check if int is nil in Obj-C
body: <p>I know in C int cannot be nil, which brings me to ask this question. I am using a rails API that uses an int for a certain property (rating). This API call could return nothing for the rating because it doesn't have a rating yet.  I am using RestKit to map the results of the API call.</p>
  
  <p>Maybe I should convert the int passed back from server API call to an NSNumber instead of an int? Or can I check in int is nil some how?</p>