title: When do strong properties get released in ARC in iOS?
body: <p>I have a quick question about ARC in iOS. (Sorry I've asked so many of these types of questions, but I'm just sooo confused regarding memory management.). It's important to note that I've never used the old memory maintenance system (<code>retain</code>, <code>release</code>, <code>assign</code>...etc) so I don't really know what those terms mean.</p>
  
  <p>Right now I'm confused regarding what I have to do to make sure that strong properties get released properly.  For example, suppose I'm making a school app and my <code>School</code> object contains strong property references to 5 different <code>Child</code> objects (not in an array). Each <code>Child</code> object has a strong pointer (property) to a <code>Book</code> object. </p>
  
  <p>If I remove one of the <code>Child</code> objects from my school (say by making its property = nil, or by changing my property to point at a new object), will its <code>Book</code> be properly released? What do I have to do to make sure that this is the case? Do I need to write <code>self.myBook = nil</code> in a <code>dealloc</code> method? What if <code>Child</code> was a View Controller, would I need to write <code>self.myBook = nil</code> in the viewDidUnload method?</p>
  
  <p>I'm targeting only iOS 5 (and up) so the old way of memory management doesn't really matter to me.</p>