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iOS Object-Oriented Swift Complex Data Structures Custom Initializers

Posted by Mackenzie Milroy
Mackenzie Milroy
3,162 Points

I need help with this initializer method. How do I fix it?

The instructions were: In the editor, I’ve declared a struct named RGBColor that models a color object in the RGB space.

Your task is to write a custom initializer method for the object. Using the initializer assign values to the first four properties. Using the values assigned to those properties create a value for the description property that is a string representation of the color object.

For example, given the values 86.0 for red, 191.0 for green, 131.0 for blue and 1.0 for alpha, each of the stored properties should hold these values and the description property should look like this:

"red: 86.0, green: 191.0, blue: 131.0, alpha: 1.0"

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 = 86.0
  self.green = 191.0
  self.blue = 131.0
  self.alpha = 1.0
  description = "red: \(self.red), green: \(self.green), blue: \(self.blue), alpha: \(self.alpha)"
  }
}

2 Answers

lvwdhydynw
lvwdhydynw
6,443 Points

Hi Mackenzie!

The problem is that you hardcode the values although in this task you should assing values using the initializer. I probably should say that you do it on an instance. It looks like this (lets assume this struct has 2 parameters, first of type Double and the second one of type Bool)

var instance = NameOfTheStruct(timeInSeconds: 81.05, finishedTheRace: true)
Rogier Nitschelm
seal-mask
.a{fill-rule:evenodd;}techdegree
Rogier Nitschelm
iOS Development Techdegree Student 5,461 Points
Rogier Nitschelm
.a{fill-rule:evenodd;}techdegree
Rogier Nitschelm
iOS Development Techdegree Student 5,461 Points

The initializer sets the properties on the newly created Struct. 

struct SomeStruct {
  var someProperty: Int
  ... 

  init(someProperty: Int) {
    self.someProperty = someProperty
  }
}

// if you now create a struct

let something = SomeStruct(someProperty: 123) 

// the initializer will receive the value passed as someProperty 

init(someProperty: Int) {    // 123 is passed in (see code above)
  self.someProperty = someProperty // the 123 is now assigned to the variable called someProperty
}