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 Extending a Native Type

Stephen Zabrecky
Stephen Zabrecky
6,298 Points
Posted by 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
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
Stephen Zabrecky
Stephen Zabrecky
6,298 Points

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