optional_03.swift

Person {
  var firstname: String
  var middlename: String?
  var lastname: String
  
  func fullName() -> () {
     print("Your fullname is \(firstname) \(middlename!) \(lastname)")
  }
}

let anotherPerson = Person(firstname: "Abel", middlename: nil, lastname: "Adeyemi")

anotherPerson.fullName() //This will throw a runtime error