iOS App Development

Please complete all the questions and you will get a

10. (8 point) What are optionals? Why are optionals needed? Why must unwrapping be done? What can go wrong with optional unwrapping? 12. (6 Point) Name a swift / iOS type is a value type. Name a Swift/iOS type that is a reference type. Explain what happens when a value type variable is assigned a new value. Do not mention parameter passing in your answer. 13. (6 point) when a downcast is necessary what would be the problem if the downcast was not done? Use an example in your explanation. 14. (6 point) The following code is from the ColorViews in-class example. what is the purpose of the function ? what the base class for the type the function is found in? How is it called? override func drawC_rect: CGRect) /Get the context being draw upon let context U!Graphics GetCurrentContext( ) Create layer if necessary checkDrawLayer (context)