print.swift

extension Features : CustomStringConvertible {
    var description : String {
        let strings = ["Alarm System", "CD Stereo", 
            "Chrome Wheels", "Pin Stripes", "Leather Interior", 
            "Undercoating", "Window Tint"]
        var members = [String]()
        for (flag, string) in strings.enumerate() where contains(Features(rawValue:1<<(flag + 1))) {
            members.append(string)
        }
        return members.description
    }
}