What is the preferred structure to a class that changes UIViewcontrollers

Im making my first big iphone app and I was wondering whats the best way of making a RootViewController that has many Navigation controllers, Tabbar, and more controllers that have no tabbar or navigation in them. I mean whats the best way to do the switching between them.

edit:

The structur looks like this:

a login/registerthey are two separate uiviewcontrollers, inside we have a tabbarcontroller that some of its views开发者_JS百科 are NavigationViewControllers. And sure u can go back to the login and register

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Sounds like a question of GUI design. So hard to answer without getting the complete picture.

It would use a tabbar only for the top level navigation. For navigating within each tab, you can use navigationbars and go as deep as necessary