Calculate age from birth date

Question

I cant find age in from birth date. What I got is

fatal error: unexpectedly found nil while unwrapping an Optional value
(lldb) 

My code

Answer 1

In Swift 2.0+ age computing code should look something like this:

extension NSDate {
    var age:Int {
        return NSCalendar.currentCalendar()
            .components(NSCalendarUnit.Year, 
                        fromDate: self, 
                        toDate: NSDate(),
                        options: NSCalendarOptions(rawValue: 0)
            .year
    }
}