Swift
Planet name is: Mercury No Planets like that: [No Planets]
The init! Failable Initializer Swift provides 'init?' to define an optional instance failable initializer. To define an implicitly unwrapped optional instance of the specific type 'init!' is specified. struct studrecord { let stname: String
init!(stname: String) { if stname.isEmpty {return nil } self.stname = stname } }
let stmark = studrecord(stname: "Swing") if let name = stmark { println("Student name is specified") }
let blankname = studrecord(stname: "") if blankname == nil { println("Student name is left blank") } When we run the above program using playground, we get the following result: Student name is specified Student name is left blank
Required Initializers To declare each and every subclass of the initialize 'required' keyword needs to be defined before the init() function. class classA { required init() { 152