Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community! While you're at it, check out some resources Treehouse students have shared here.

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

iOS Intermediate Swift Extensions and Protocols Protocol Extensions

Kimanie Williams
Kimanie Williams
5,472 Points
Posted by Kimanie Williams
Kimanie Williams
5,472 Points

Do not understand what I am doing wrong

Im confused

protocols.swift 
protocol Calculator {
  func square(_ value: Double) -> Double
}

// Enter your code below
extension Math {
    func square(_ value: Double) -> Double {
        guard let mycares = value(self) else {
            return nil 
        }
        return mycares * value
    }
}

1 Answer

Arman Arutyunov
Arman Arutyunov
21,900 Points
Arman Arutyunov
Arman Arutyunov
21,900 Points

The extension should be of a Calculator protocol. And it should contain an implementation of that protocol's method. The method should return a squared value of your parameter "value". That's just value * value.

protocol Calculator {
  func square(_ value: Double) -> Double
}

// Enter your code below

extension Calculator {
  func square(_ value: Double) -> Double {
    return value*value
  }
}

Hope it helps!