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iOS Object-Oriented Swift 2.0 Complex Data Structures Custom Initializers

Sheng Wei
Sheng Wei
4,382 Points
Posted by Sheng Wei
Sheng Wei
4,382 Points

[Help!] What does using my own custom initialiser for my init method mean?

This topic is doable, but the Bummer I keep getting is: Don't use the member wise initialisers given by swift, use your own custom initialisers. This wasn't really explained in the video so Im not sure what it means. Also, do I use string interpolation to represent the description? Much Appreciated!

structs.swift 
struct RGBColor {
    let red: Double
    let green: Double
    let blue: Double
    let alpha: Double

    let description: String

    // Add your code below
    init(red: Double, green: Double,  blue: Double, alpha: Double, description: String){
        self.red = red
        self.green = green
        self.blue = blue
        self.alpha = alpha
        self.description = red, green, blue, alpha

    }

}

1 Answer

jcorum
jcorum
71,830 Points

Wei Pang, what they want is for the description to be a String in the described format:

    init(red: Double, green: Double,  blue: Double, alpha: Double){
        self.red = red
        self.green = green
        self.blue = blue
        self.alpha = alpha
        description = "red: \(red), green: \(green), blue: \(blue), alpha: \(alpha)"
    }

So if you create an RGBColor object you can ask for its description and get the String back saying what the value is for red, green, blue and alpha.

Note that you don't need self in front of description because there is no ambiguity as to which is the member variable.

Sheng Wei
Sheng Wei
4,382 Points
Sheng Wei
Sheng Wei
4,382 Points

Thanks a lot jcorum! Your explanations are really clear :)