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iOS Intermediate Swift Extensions and Protocols Extending a Native Type

Richard Sun
Richard Sun
11,257 Points
Posted by Richard Sun
Richard Sun
11,257 Points

Why does Treehouse say that I haven't added an add method?

Treehouse says that I haven't added an Add Method and one that returns an int even though I have. What is wrong?

types.swift 
// Enter your code below
extension String {
    func add(value: Int) -> Int {
        do {
            let num = Int(self)
            return num! + value
        } catch {
            return nil
        }
    }
}

1 Answer

Jeff McDivitt
Jeff McDivitt
23,970 Points
Jeff McDivitt
Jeff McDivitt
23,970 Points

The easiest way to handle this is to make the return Int an optional and use a guard statement

    func add(value: Int) -> Int?{
        guard let convertedNumber = Int(self) else{
            return nil
        }

        return convertedNumber + value
    }

}