Push and pop

We saw in the preceding example how to navigate to another view controller using segues. Additionally, we can do this programmatically by calling the following:

self.navigationController?.pushViewController(viewController, animated: true) 

This pushes a new view controller with or without animation.

Also, to pop view controllers, we have three functions that we can use:

• The popViewControllerAnimated function: This will pop the top view controller and update the UI to the preceding one
• The popToRootViewControllerAnimated function: This will pop all view controllers in the stack, but the root view controller
• The popToViewController:animated function: This will pop all view controllers in the stack not upto the root but upto a given reference to the view controller to pop to it