Login Controller segue to TabBar Controller keeps crashing in 'MyLocations'

I’m trying to attach a login controller to tabbar controller. My Login Controller modal segue to TabBar Controller keeps crashing in ‘MyLocations’; the file I’m working with from iOS Apprentice. Any suggestions would be great.

You have some variable that is nil. It’s hard to say what is going wrong without more info.

On what line does the app crash?

MIH. Awesome! You made ‘MyLocations’. It’s a pleasure to be chatting with you. Here’s my screenshot:

Note the error message about casting Lousy_car.DigitsViewController to UITabBarController. That’s probably related to the crash.

I deleted the tabbar function in app delegate. The segue worked but the app crashes when you click a tab bar item. I added the function back in so I’m back to square one.

Whats your contact info?

I fixed it! The mistake was I made a UIViewController when I should’ve made a TabBarController. Rookie mistake. I’m learning.

Now the app crashes when 2/4 view controllers segued from the tab bar are selected. The two controllers also have a navigation controller embedded within them.