Optional instances

Both struct and class objects may be declared as optionals, as follows:

let secondDriver: Driver? = Driver(name: "Fred", 
                                   yearOfBirth: 1904) 

An optional instance's properties can be assigned to an optional variable as follows:

var nameOnSchedule:String? 
nameOnSchedule = secondDriver?.name 

Note that, by making nameOnSchedule an optional, we can assign it to be the name of secondDriver, if there is one, or nil if there is not, without having to test explicitly.