如何在UIViewControllers之间切换而不使用标签栏?

I have a UINavigationController. In the 2nd level of my hierarchy, I want to show a view controller with a toolbar in which I inserted a segmented control. Through it the user can select between two "views" of the same page that we can call A and B (like in the Calendar application).I have a UINavigationController. In the 2nd lev