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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
Posted by 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
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
        }
    }
}