Object Mapping in swift - ios

Question

Hello i'm beginner in Swift programming.
Im trying to make an app with login, which will take user and pass data, parse to JSON and send it to server.
I need to able that an user take only two values: user and pass from field, parse the whole object into JSON and send post request.
Before all that i have problem with making User struc for mapping: error is on the end of init " Return from initializer without initialising all sorted properties".
struct User: Mappable{
private var _username: String!
private var _password: String!
private var _firstname: String
private var _lastname: String
var username: String{
get{
return _username
}set(username){
self._username = username
}
}
var password: String{
get{
return _password
}set(password){
self._password = password
}
}
var firstname: String{
get{
return _firstname
}set(firstname){
self._firstname = firstname
}
}
var lastname: String{
get{
return _lastname
}set(lastname){
self._lastname = lastname
}
}
init(username: String, password: String){
self._username = username
self._password = password
}
init?(_ map: Map) {
}
mutating func mapping(map: Map) {
username <- map["USERNAME"]
password <- map["PASSWORD"]
firstname <- map["FIRST_NAME"]
lastname <- map["LAST_NAME"]
}
}
I know i have to learn so much, but right now don't have time, so must finish this. I'm trying to learn as much as it possible.
Thank you so much

Answer 1

All of your non-optional properties must be initialized prior to exiting your init methods. Setting them to empty strings (or whatever) should eliminate the error.
init(username: String, password: String){
self._username = username
self._password = password
self._firstname = ""
self._lastname = ""
}
init?(_ map: Map) {
self._username = ""
self._password = ""
self._firstname = ""
self._lastname = ""
}
Alternately you could make those properties optional.