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iOS Intermediate Swift Extensions and Protocols Extending a Native Type

Stephen Zabrecky
Stephen Zabrecky
6,298 Points

This works in Playgrounds but not on Treehouse

What am I missing? The code I've written works correctly in Swift Playgrounds but the coding challenge won't accept my answer.

types.swift
// Enter your code below

extension String {
    func addToString(intToAdd: Int)-> Int? {
        guard let stringInt = Int(self) else {
            return nil
        }
        return stringInt + intToAdd
    }
}

1 Answer

Dhanish Gajjar
Dhanish Gajjar
20,185 Points

Hey Stephen Zabrecky, the challenge editor is very specific about names, arguments etc. So the function has to say add not addToString

extension String {
    func add(value: Int) -> Int? {
        guard let stringValue = Int(self) else {
            return nil
        }
        return stringValue + value
    }
}
Stephen Zabrecky
Stephen Zabrecky
6,298 Points

Ah, okay. I'll keep that in mind for next time. Thank you!