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

Mark DeMItchell
Mark DeMItchell
1,527 Points

Difficulty understanding syntax in subclass.

Hoping to get clarity on my subclass "Robots". Inside of my switch statement I am confused on how to move the actual x & Y coordinate with the correct syntax. How do I refer to the Superclasses position?

Additionally, do I need to include a new initializer for my Robot subclass?

Thanks

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

1 Answer

Jeff McDivitt
Jeff McDivitt
23,970 Points

Hoping to get clarity on my subclass "Robots". Inside of my switch statement I am confused on how to move the actual x & Y coordinate with the correct syntax. You have this part correct the issue is that it looks like you changed the initial method in the superclass for move _ direction to direction. And no you do not need a new initializer to override a method.

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)
    }

//Leave this function alone    
    func move(_ direction: String) {
        print("Do nothing! I'm a machine!")
    }
}

// Enter your code below

class Robot: Machine {
//Your override will then be correct and the rest of your code is good
    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
        }
    }
}