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

Posted by Sampath Kumar Maka
Sampath Kumar Maka
2,840 Points

Able to get the expected output in Playground but the same code is giving errors in the compiler

I have instantiated the objects as well and the same code compiled in the playground and I got the output as well but where as in the compiler here, it is throwing the errors.

Can anyone help me out please.

robots.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! I'm a machine!")
  }
}

class Robot: Machine {

      override func move(direction: String) {

        switch direction {

        case "Up" :
            location.y += 1; break
        case "Down":
            location.y -= 1; break
        case "Left" :
            location.x -= 1; break
        case "Right" :
            location.x += 1; break
        default:
            break

        }

    }

}

3 Answers

Jeff McDivitt
Jeff McDivitt
23,970 Points

You only need a break statement at the end 

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! I'm a machine!")
    }
}

class Robot: Machine{

    override func move(_ direction: String) {
        switch direction {
        case "Up":    location.y += 1
        case "Down":  location.y -= 1
        case "Right": location.x += 1
        case "Left":  location.x -= 1
        default:
            break
        }
    }
}
Sampath Kumar Maka
Sampath Kumar Maka
2,840 Points

Hi Jeff, thanks for the reply, but I have tried with single break also, even then it didnt pass the challenge, where as the same code was giving the expected output in the play ground.

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

Hi Sampath - The code I posted will pass the challenge and is correct, it could also be because you have semicolons at the end of each return case statement.

Sampath Kumar Maka
Sampath Kumar Maka
2,840 Points

Thanks Jeff, it worked.

Dhanish Gajjar
Dhanish Gajjar
20,185 Points
Dhanish Gajjar
Dhanish Gajjar
20,185 Points

Sampath Kumar Maka The solution Jeff McDivitt gave, is correct. When the challenge loads, the function direction in the class Machine, has the external name omitted with an underscore. While overriding the same function in the class Robot, it also has to be omitted. Xcode hints at that error, however the challenge editor has no features like that. I don't understand why you removed it from the original class of Machine as well. Hope it helps.

Sampath Kumar Maka
Sampath Kumar Maka
2,840 Points

Thanks Danish, it worked and I passed the challenge too.