Checking the right answer
This recipe will complete the previous one by checking the user's answer. If for any reason the answer receives a value out of range, this will be set to nil. Of course, in this application, it's not possible to answer with a wrong value, but remember that a good developer is always thinking about the possible software evolution.
Getting ready
Copy the previous recipe; if you like, you can rename the product name to Chapter 2 Examination 2 by simply renaming the target name, as shown here:
How to do it...
Follow these steps in order to check the answers:
Go to the
question.swiftfile. Now, replace the current class with the following one:struct Question { var question:String var answer1:String var answer2:String var answer3:String var rightAnswer:Int var userAnswer:Int? { willSet(newAnswer){ if newAnswer? < 2 || newAnswer? > 3 { userAnswer = nil println("Wrong value, fixing it") ...