Using the Delegate Pattern

In iOS programming, it is common to use the delegate pattern for one component to pass information to another. The delegator component defines a delegate protocol with functions that it can use to pass out information. The delegatee component implements the provided delegate protocol by overriding the protocol's functions and handles the received information.

In your case, the new screen for adding a new entry is the delegator, while the main screen with table view is the delegatee to whom the information is passed.

Create the following delegate protocol in the same Swift file as the EntryDetailsViewController class (delegator) so it can inform MainScreenViewController (delegatee) when user is done creating the new entry:

protocol EntryDetailsViewControllerDelegate: class {
    // Delegate Cancel Event
    func entryDetailsViewControllerDidCancel...