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iOS Intermediate Swift Extensions and Protocols Extending a Native Type

Jose Portuondo-Dember
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Jose Portuondo-Dember
iOS Development Techdegree Student 5,275 Points
Posted by Jose Portuondo-Dember
.a{fill-rule:evenodd;}techdegree
Jose Portuondo-Dember
iOS Development Techdegree Student 5,275 Points

Help me fix this error: "Bummer! Make sure you're adding an add method that takes an Int and returns Int?"

No matter what I try, including straight up copy-pasting solutions that others have posted success with, I keep getting the same error: "Bummer! Make sure you're adding an add method that takes an Int and returns Int?"

my code works fine in playground, and returns an Int? wrapped in optional(). I am at my wit's end. Any suggestions are welcome.

types.swift 
// Enter your code below
extension String {
    func add(_ value: Int) -> Int? {
        guard let originalStringAsInteger = Int(self) else {
            return nil
        }
            return originalStringAsInteger + value)


    }
}

2 Answers

andren
andren
28,558 Points
andren
andren
28,558 Points

The issue is the external parameter name you have added, the instructions does not ask you to name the parameter _ externally. In the example provided value is the parameter name used when calling the method.

If you remove the external name like this:

extension String {
    func add(value: Int) -> Int? {
        guard let originalStringAsInteger = Int(self) else {
            return nil
        }
        return originalStringAsInteger + value
    }
}

Then the code will be accepted.