How to make all viewController see the variable?

Question

iOS

1) there is a value that one of the viewController receives, how to make it so that all viewController can see it??
2) And the very essence of the problem is that there is a viewController in it ViewContainer containing viewController2 how, when loading the first viewKotreller, pass a variable to the viewController2 which is in the viewContainer?

Answer 1

1) to forward in each controller handles
2) the word static is familiar?
3) use some singleton
4) maybe use DI

Answer 2

Use NSNotificationCenter or delegates, here is a general article .