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

JUNSEI TEI
JUNSEI TEI
2,055 Points
Posted by JUNSEI TEI
JUNSEI TEI
2,055 Points

HELP

Can anyone help me explain a bit, what should be the parameter in override init(), and what should be the parameter in super.init(), both for this question and in general. I get confused with these concepts. And as well, why I cannot use location.x and location.y in the subclass. Does it has anything to do with my wrong override initialization?

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! I'm a machine!")
    }
}

// Enter your code below
class Robot: Machine{
    override init(){
        super.init(location: Point1(x: 0, y: 0))
    }
}
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
    }
}

1 Answer

Steve Hunter
Steve Hunter
57,682 Points

Hi there,

I don't think you need to override the init method. Also, your func needs to be inside the class. Then, if you remove the spaces between location.x etc. and the increment and decrement operators; it'll work 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
    }
  }
}

Steve.