why “present modal view controller”?

Question

Just curious about the modal view controller usage. When and why should we use them? Is there a guideline?

I found the sample core data book code create a navigatio

Answer 1

Generally you use modal view controllers to focus the user's attention on a Task. When you push, the user is in some kind of navigation flow, but still has the total application at their fingertips. They might decide to go forward or backward, switch to a different tab in the middle, whatever. When they get a modal view controller, they can't do any of that until the task is completed or canceled out of (the modal view is dismissed).

Pls refer why does this code use presentModalViewController? (not pushViewController) also