Before we can discuss Automatic Reference Counting, ARC for short, you need to understand the difference between value types and reference types.

In the previous installment of this series, you learned about Automatic Reference Counting and how it helps keep memory management in check. Remember that a class instance is deallocated if no properties, constants, or variables hold a strong reference to the class instance. I didn't explain what a strong reference is, though.

Strong reference cycles negatively impact your application's performance. They lead to memory leaks and unexpected behavior that is often hard to debug. In this episode, I show you how to resolve the strong reference cycles we created in the previous episode of this series.

In the previous episode of Understanding Swift Memory Management, you learned how weak and unowned references can break a strong reference cycle. What sets weak and unowned references apart from strong references? What is the difference between weak and unowned references? When is it appropriate to choose an unowned reference over a weak reference? We tackle these questions in this episode.

If you have been paying attention, then you may have noticed that we haven't resolved the strong reference cycle we introduced between the root view controller and the settings view controller earlier in this series.