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iOS Build a Simple iPhone App with Swift 2.0 Getting Started with iOS Development Swift Recap Part 2

Dragan Ceriman
Dragan Ceriman
1,215 Points
Posted by Dragan Ceriman
Dragan Ceriman
1,215 Points

Code not compiled even though it is correct

Even though code is compiled and running OK in xcode, does not even compile in code challenge. Therefore, can not proceed. :)

I removed ' from string "i'm a machine" since it commented out all of my code.

classes.swift 
class Point {
    var x: Int
    var y: Int

    init(x: Int, y: Int){
        self.x = x
        self.y = y
    }
}


class Machine {
    var location: Point

    init() {
        self.location = Point(x: 0, y: 0)
    }

    func move(direction: String) {
        print("Do nothing! Im a machine!")
    }
}

// Enter your code below
class Robot: Machine {
    init(x: Int, y: Int) {
        super.init()
        self.location.x = x
        self.location.y = y
    }
    override func move(direction: String) {
        switch direction {
        case "Up":
            self.location.y += 1
        case "Down":
            self.location.y -= 1
        case "Left":
            self.location.x -= 1
        case "Right":
            self.location.x += 1
        default:
            break
        }
    }
}

4 Answers

Steve Hunter
Steve Hunter
57,712 Points

Hi Dragan,

The only thing here is that you don't need to rewrite the init method. Remove that part of your code and the rest is fine. 

class Robot: Machine {
    override func move(direction: String) {
        switch direction {
          case "Up": location.y++
          case "Down": location.y--
          case "Left": location.x--
          case "Right": location.x++
          default: break
        }
    }
}

Deleting the apostrophe makes no difference, but you can escape it with a backslash else it does mess with the formatting in the code window, which is annoying! 

    func move(direction: String) {
        print("Do nothing! I\'m a machine!")
    }

I hope that helps,

Steve.

Steve Hunter
Steve Hunter
57,712 Points

:smile:

Jason Anders
MOD
Jason Anders
Treehouse Moderator 145,860 Points
Jason Anders
Jason Anders
Treehouse Moderator 145,860 Points

Hey Dragan,

Yes, this is a glitch in the code challenge and the Support Team has been made aware.

In the meantime, you can't remove the ', but you can escape it - add a backslash before the single quotation mark.

        print("Do nothing! I\'m a machine!")

However, there is also an error in your code. You added an unnecessary init statement for the subclass of Robot. Robot is inheriting everything from its Super Class of Machine, so you don't have to re-initialize them.

Additionally, the self.location can be just location but either work... the latter is just less typing.

The completed code from the affected line will be:

       print("Do nothing! I\'m a machine!")
    }
}

// Enter your code below
class Robot: Machine {
    override func move(direction: String) {
        switch direction {
        case "Up":
            self.location.y += 1
        case "Down":
            self.location.y -= 1
        case "Left":
            self.location.x -= 1
        case "Right":
            self.location.x += 1
        default:
            break
        }
    }
}

I apologize it took this long for someone to address the problem for you.

Keep Coding! :)

Dragan Ceriman
Dragan Ceriman
1,215 Points
Dragan Ceriman
Dragan Ceriman
1,215 Points

Thank you for your answers. I thought that my version would be better since you can put any location and not only (0,0) :) But, nevertheless, many thanks!

Steve Hunter
Steve Hunter
57,712 Points

Hi Dragan,

I agree that the functionality that you added does make sense. However, the compiler doesn't know that, unfortunately, so it wouldn't know how to instantiate a Robot. The behind-the-scenes tests wouldn't be generated to pass in two integers as parameters so no Robot object would be generated. This would mean the compiler fails your code.

Make sense?

Steve.