title: Passing data between view controllers
body: <p>I'm new to iOS and Objective-C and the whole <a href="https://en.wikipedia.org/wiki/Model%E2%80%93view%E2%80%93controller" rel="noreferrer">MVC</a> paradigm and I'm stuck with the following:</p>
  <p>I have a view that acts as a data entry form and I want to give the user the option to select multiple products. The products are listed on another view with a <code>UITableViewController</code> and I have enabled multiple selections.</p>
  <p>How do I transfer the data from one view to another? I will be holding the selections on the <code>UITableView</code> in an array, but how do I then pass that back to the previous data entry form view so it can be saved along with the other data to Core Data on submission of the form?</p>
  <p>I have surfed around and seen some people declare an array in the app delegate. I read something about <a href="https://en.wikipedia.org/wiki/Singleton_pattern" rel="noreferrer">singletons</a>, but I don't understand what these are and I read something about creating a data model.</p>
  <p>What would be the correct way of performing this and how would I go about it?</p>