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iOS Functions in Swift Adding Power to Functions Returning Complex Values

Michele Livingston
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.a{fill-rule:evenodd;}techdegree
Michele Livingston
iOS Development Techdegree Student 808 Points
Posted by Michele Livingston
.a{fill-rule:evenodd;}techdegree
Michele Livingston
iOS Development Techdegree Student 808 Points

Need help with accepting a single parameter

In this challenge, we have the following geographical coordinates

Eiffel Tower - lat: 48.8582, lon: 2.2945 Great Pyramid - lat: 29.9792, lon: 31.1344 Sydney Opera House - lat: 33.8587, lon: 151.2140

Declare a function named coordinates that takes a single parameter of type String, with an external name for, a local name of location, and returns a tuple containing two Double values (Note: You do not have to name the return values). For example, if I use your function and pass in the string "Eiffel Tower" as an argument, I should get (48.8582, 2.2945) as the value. If a string is passed in that doesn’t match the set above, return (0,0)

Getting an error that says: Make sure you accept a single parameter of type String in your function declaration

functions.swift 
// Enter your code below
func coordinates(forLocation: String) -> (Double, Double) {

    switch location{
    case "Eiffel Tower" =  lat: 48.8582, Ion: 2.2945
    case "Great Pyramid" = lat:(29.9792, Ion: 31.1344
    case "Sydney Opera House" =  Lat: 33.8587, Ion: 151.2140

        default: (0,0)
        }

        return (lat, Ion)
}


let result: = coordinates(forLocation: Eiffel Tower)

2 Answers

Ryan Lee
Ryan Lee
13,806 Points
Ryan Lee
Ryan Lee
13,806 Points

Awesome, you almost got it. One thing you forgot to do was add a return statement for your default case and also change the Ints to Doubles since that is what we specified that we are returning. Also, since we are returning on each case, we do not need a return statement at the bottom of the function.

func coordinates(forLocation: String) -> (Double, Double) {

   switch forLocation{
     case "Eiffel Tower":  return (lat: 48.8582, Ion: 2.2945)
     case "Great Pyramid": return (lat:29.9792, Ion: 31.1344)
     case "Sydney Opera House":  return (lat: 33.8587, Ion: 151.2140)
     default: return (0.0,0.0)
  }
}


let result = coordinates(forLocation: "Eiffel Tower")
Ryan Lee
Ryan Lee
13,806 Points
Ryan Lee
Ryan Lee
13,806 Points

Hi Michele,

You may have already found your answer but just in case... Here are the issues I found with your code:

  1. You are switching on "location" however, that isn't the argument label that we're passing in so the compiler won't know what you mean. Try switching on "forLocation", this will hold whatever string the user passes in when they call the function (i.e. let result: = coordinates(forLocation: Eiffel Tower))

  2. It would probably help to review the proper syntax for switch statements. I did a quick google search for "switch syntax swift" myself to double check how it should be formatted.

  3. In your default case you are using Ints, change those to the type you have specified to the compiler that you are returning (double or 0.0, 0.0)

  4. Lastly, in your return statement you are trying to return a tuple that contains two variables (lat and Ion). However, these variables are never declared. Try returning the result or the value in your switch statement. Another words, instead of saying:

case "Eiffel Tower": (lat: 48.8582, Ion: 2.2945)

you want to say:

case "Eiffel Tower": return (lat: 48.8582, Ion: 2.2945)

This means, in the case of "Eiffel Tower" being input by the user, I want you to return this tuple containing these two doubles labeled lat and Ion

Feel free to reply if it's still not working and I'll try to provide a clearer explanation. Good luck!

Michele Livingston
seal-mask
.a{fill-rule:evenodd;}techdegree
Michele Livingston
iOS Development Techdegree Student 808 Points
Michele Livingston
.a{fill-rule:evenodd;}techdegree
Michele Livingston
iOS Development Techdegree Student 808 Points

Thank you for your help. I made changes to the code and the preview does not show any errors but it is still not being excepted. I still get the comment: Make sure you accept a single parameter of type String in your function declaration. Here is the new code

func coordinates(forLocation: String) -> (Double, Double) {

switch forLocation{
case "Eiffel Tower": return(48.8582,  2.2945)
case "Great Pyramid": return(29.9792, 31.1344)
case "Sydney Opera House": return(33.8587, 151.2140)

    default: (0, 0)
    }

    return (0.0, 0.0)

}