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iOS Swift 2.0 Protocols Creating Flexible Objects Using Protocols Protocol Inheritance

Erman Sahin Tatar
Erman Sahin Tatar
3,223 Points
Posted by Erman Sahin Tatar
Erman Sahin Tatar
3,223 Points

Protocols in swift, Make sure Dog object conforms to PetType Error

it gives the error, Help me which part I misunderstood the topic I cant figure out 

protocol AnimalType {
  var numberOfLegs: Int { get }
}

protocol PetType: AnimalType {
  var numberOfLegs: Int { get }
  var cuddlyName: String { get }
}

struct Dog : PetType {
  var numberOfLegs: Int
  var cuddlyName: String 

  init(numberOfLegs: Int, cuddlyName: String){
    self.numberOfLegs = numberOfLegs
    self.cuddlyName = cuddlyName

  }

}
protocols.swift 
protocol AnimalType {
  var numberOfLegs: Int { get }
}

2 Answers

Steven Deutsch
Steven Deutsch
21,046 Points
Steven Deutsch
Steven Deutsch
21,046 Points

Hey Erman Sahin Tatar,

Your protocol requires that the variable stored properties numberOfLegs and cuddlyName are readable, so you need to provide a way for them to be retrieved using get. You don't need an initializer, the memberwise initializer is provided automatically for structures.

protocol AnimalType {
  var numberOfLegs: Int { get }
}

protocol PetType: AnimalType {
  var numberOfLegs: Int { get }
  var cuddlyName: String { get }
}

struct Dog: PetType {
  var numberOfLegs: Int { 
    get {
      return numberOfLegs
    } 
  }
  var cuddlyName: String {
    get {
       return cuddlyName
    }
  }
}

Hope this helps!

Nathan Tallack
Nathan Tallack
22,159 Points
Nathan Tallack
Nathan Tallack
22,159 Points

Note no space between the Dog and the colon on the struct declaration line for Dog. :)