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iOS Object-Oriented Swift Complex Data Structures Custom Initializers

Posted by Balazs Meyrhuber
Balazs Meyrhuber
986 Points

I can´t solve the string interpolation in this excercise

Can somebody please help me to solve this challenge

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) {
        self.red = red
        self.green = green
        self.blue = blue
        self.alpha = alpha
        self.description =
        RGBColor(red: 86.0, green: 191.0, blue: 131.0, alpha: 1.0)

    }
}

4 Answers

Greg Kaleka
Greg Kaleka
39,021 Points
Greg Kaleka
Greg Kaleka
39,021 Points

Hi Balazs,

You've almost got it, but you need to use string interpolation for the description! We definitely don't want to hard-code in values for the description. If we do that, we could create a RGB color that's 100% blue, and the description would still be the color you hard-coded in. Also, your description is an RGBColor, but it should just be a simple string. The idea is that someone can call print(myColor.description) and get an output that describes the color. The example given is that it should print "red: 86.0, green: 191.0, blue: 131.0, alpha: 1.0", but those values should match whatever is in the instance.

Instead, you need to use string interpolation.

description.swift 
self.description = "red: \(), green: \(), blue: \(), alpha: \())"

You know what to fill in inside those parentheses, right? You got this!

Let me know if anything doesn't make sense.

Cheers :beers:

-Greg

Balazs Meyrhuber
Balazs Meyrhuber
986 Points
Balazs Meyrhuber
Balazs Meyrhuber
986 Points 
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) {
        self.red = red
        self.green = green
        self.blue = blue
        self.alpha = alpha
        self.description = "red: \(red), green: \(green), blue: \(blue), alpha: \(alpha))"
    }
}

I changed it now and it still isn´t working what else do I need to do?

Greg Kaleka
Greg Kaleka
39,021 Points
Greg Kaleka
Greg Kaleka
39,021 Points

You got it - you just have an extra closing parenthesis in your string (at the end). Delete that and you're good to go.

Balazs Meyrhuber
Balazs Meyrhuber
986 Points
Balazs Meyrhuber
Balazs Meyrhuber
986 Points

Thank you Greg it worked

Greg Kaleka
Greg Kaleka
39,021 Points
Greg Kaleka
Greg Kaleka
39,021 Points

Hi Giorgos,

Please refrain from posting answers to challenges without any explanation. It doesn't help students learn!

Instead, try to explain what the student did right, what they did wrong, and maybe provide the solution, but often it's better to let them figure it out with you getting them most of the way there.