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iOS Swift 2.0 Functions Function Parameters Returning Complex Values

Greg Stone
Greg Stone
2,705 Points
Posted by Greg Stone
Greg Stone
2,705 Points

Stuck. Getting error 'Cannot convert return of type "String" to return type "(Double, Double). How do I convert?

Stuck. Getting error 'Cannot convert return of type "String" to return type "(Double, Double). How do I convert?

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

    switch location {
    case "Eiffel Tower": 48.8582; 2.2945
    case "Great Pyramid": 29.9792; 31.1344
    case "Sydney Opera House": 33.8587; 151.2140
    default: 0; 0
    }

    return location
}

1 Answer

Anjali Pasupathy
Anjali Pasupathy
28,883 Points
Anjali Pasupathy
Anjali Pasupathy
28,883 Points

With the way you've structured your solution, you're returning the String location. What you need to return are the coordinates (which should be structured as (Double, Double), not Double; Double).

One way you could do this is by writing all the case blocks and the default blocks as return statements. Another way to do this would be to create a coordinates variable of type (Double, Double) before the switch statement, assign the coordinate values to coordinates inside each case block and the default block, and return coordinates.

func getTowerCoordinates (location: String) -> (Double, Double) {

    var coordinates: (Double, Double) // DECLARE coordinates VARIABLE OF TYPE (Double, Double)
    switch location { // ASSIGN LONGITUDE AND LATITUDE TO coordinates IN (Double, Double) FORMAT
    case "Eiffel Tower": coordinates = (48.8582, 2.2945)
    case "Great Pyramid": coordinates = (29.9792, 31.1344)
    case "Sydney Opera House": coordinates = (33.8587, 151.2140)
    default: coordinates = (0, 0)
    }

    return coordinates // RETURN coordinates RATHER THAN location
}

I hope this helps!

Greg Stone
Greg Stone
2,705 Points
Greg Stone
Greg Stone
2,705 Points

Interesting. What you're having me do isn't quite something I've learned yet in this course -and some of your steps are opposed to the teachers instructions. Though I'm sure your code works in the real world, there must be another way to solve this as your code is not passing my code challenge.

Anjali Pasupathy
Anjali Pasupathy
28,883 Points
Anjali Pasupathy
Anjali Pasupathy
28,883 Points

That is strange. I tested my code in the quiz challenge, and it passed.

I'm pretty sure what I'm having you do is well within the bounds of what you should have learned if you're on the Swift 2 track. I apologize if anything in my explanation confused you.

The relevant instructions in the challenge are as follows:

"Declare a function named getTowerCoordinates that takes a single parameter of type String, named location, and returns a tuple containing two Double values (Note: You do not have to name the return values)

Use a switch statement to switch on the string passed in to return the right set of coordinate values for the location."

The only difference between the code I wrote and the specifications in the instructions is, rather than return the coordinates ("a tuple containing two Double values", which is structured as (Double, Double)), I created a variable named coordinates of type (Double, Double), set coordinates to the correct value using the switch statement, and returned coordinates.

If you like, I could restructure the function and point out which parts of the code conform to which parts of the instructions.

/*
 Declare a function named getTowerCoordinates
 that takes a single parameter of type String, named location,
 and returns a tuple containing two Double values
*/
func getTowerCoordinates (location: String) -> (Double, Double) {
    /*
     Use a switch statement to switch on the string passed in to
     return the right set of coordinate values for the location.

     returns a tuple containing two Double values
    */
    switch location {
    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: return (0, 0)
    }
}

I hope this clarifies the issue.