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

Ruben Mercado
Ruben Mercado
1,933 Points

not sure how to connect the x and y

im not sure how to connect the x and y values

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 am a machine!")
    }
}

// Enter your code below

class Robot: Machine{
    override func move(_ direction: String) {
        switch direction {
            case "Up": y += 1
            case "Down": y -= 1
            case "left": x -= 1
            case "Right": x += 1
        default: break

        }
    }
}

1 Answer

Matthew Long
Matthew Long
28,369 Points

Like before, if you use Xcode you would see an error saying "'y' is an unresolved identifier". This is basically saying it doesn't know what y is. This is when you tell it that y is the y property of location that is an instance of Point:

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 am a machine!")
  }
}

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

Also, make sure the "L" in Left is capitalized.