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iOS Object-Oriented Swift 2.0 Class Inheritance Overriding Methods

Posted by Billy Potts
Billy Potts
Courses Plus Student 2,344 Points

can someone tell me what was my mistake with this subclass

I've provided a base class Person in the editor below. Once an instance of Person is created, you can call getFullName() and get a person's full name.

Your job is to create a class named Doctor that overrides the getFullName() method. Once you have a class definition, create an instance and assign it to a constant named someDoctor.

For example, given the first name "Sam", and last name "Smith", calling getFullName() on an instance of Person would return "Sam Smith", but calling the same method on an instance of Doctor would return "Dr. Smith".

classes.swift 
class Person {
    let firstName: String
    let lastName: String

    init(firstName: String, lastName: String) {
        self.firstName = firstName
        self.lastName = lastName
    }

    func getFullName() -> String {
        return "\(firstName) \(lastName)"
    }
}

// Enter your code below
class Doctor: Person {
 override init(firstName: String, lastName: String) {
 super.init(firstName: "Dr.", lastName: "Smith")
 }
 override func getFullName() -> String {
 return "\(firstName) \(lastName)"
 }
 }
 let someDoctor = Doctor(firstName:"Dr.", lastName: "Smith")

1 Answer

jcorum
jcorum
71,830 Points
jcorum
jcorum
71,830 Points

You don't need an initializer as Doctor has no new stored properties. Nor do you need to call the superclass's initializer. The purpose of the overriding function was to return something different, viz., "Dr. ---"

// Enter your code below
class Doctor: Person {  

    override func getFullName() -> String {
        return "Dr. \(lastName)"
    }
}

let someDoctor = Doctor(firstName: "Sam", lastName: "Smith")

Finally, when you create a Doctor object you need to give both a first and last name, as you need to fill both of the inherited stored properties.

The difference is that if you call the getFullName() method on a Doctor object like someDoctor you will get back the String "Dr. Smith" rather than "Sam Smith".