You should use letters or numbers ...
--- > A
A < - B
A - > B
In any case, once you pop B, you can not go back to B again. You will need to create a new instance of B and push.
Also, if what you want (in a < - B) is to go back to the immediately previous controller, you should use popViewController
instead of popToRootViewController
.
In this case, it coincides that your rootViewController is also the one immediately before B, but this could happen to you:
A - B - C
popToRootViewController
: A < - C (only A)
popViewController
: A - B < - C (would be B and behind would still be A)