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iOS Object-Oriented Swift Class Inheritance Overriding Methods

theo Vog
theo Vog
2,289 Points
Posted by theo Vog
theo Vog
2,289 Points

Help on how to override the function

Hello,

I don't know what's the problem with my code, can someone EXPLAIN me what's wrong ? I just want to understand :-)

Thanks !

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

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

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

class Doctor: Person {

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

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

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

2 Answers

theo Vog
theo Vog
2,289 Points
theo Vog
theo Vog
2,289 Points

Allright! I just found the solution by my own.

But I don't understand everything. Why I don't need to write the initialization here ? Can someone provide me with super clear explanations ?

class Person {
    let firstName: String
    let lastName: String

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

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

class Doctor: Person {

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

let someDoctor = Doctor(firstName: "Sam", lastName: "Smith")
someDoctor.fullName()
Jhoan Arango
Jhoan Arango
14,575 Points
Jhoan Arango
Jhoan Arango
14,575 Points

Hello,

The reason why you do not have to write your own initializer it's because "Doctor" is inheriting the initializer from it's super class "Person". Not only it's inheriting the initializer, but all of the properties. By overriding the method, you are now creating your own Implementation of the method, meaning that you will not be directly using the inherited method, but your own.

If you had added an extra property to "Doctor", then you may add a new initializer to it.

I hope this helps you clear a bit. If you need a better explanation please let me know.

Good luck