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iOS Intermediate Swift Extensions and Protocols Protocol Extensions

Richard Pitts
PLUS
Richard Pitts
Courses Plus Student 1,243 Points

Not Sure on this one either!

What is the correct answer?

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

extension Calculator {
  func square(_ value: Double) -> Double
}
// Enter your code below

1 Answer

David Papandrew
David Papandrew
8,386 Points

Hi Richard,

Remember that the protocol just tells you what you need to include but not how. So the protocol will only include the function name and signature (params and return type).

So when you write the extension, you need to write out a fully working function (that also conforms to the protocol).

To do this, you will want to include a return statement inside the body of the function.

Here is the code:

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

// Enter your code below
extension Calculator {
  func square(_ value: Double) -> Double {
    return value * value
  }
}