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

Junaid Shaikh
Junaid Shaikh
5,918 Points
Posted by Junaid Shaikh
Junaid Shaikh
5,918 Points

In the editor you've been provided with two classes - Point to represent a coordinate point and Machine. The machine has

how solve it

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!")
    }
}
class Robot: Machine {
    var location2: Point
    var x1: Int
    var y1: Int
    override init() {
      super.init(direction: String,x: x1,y: y1)
      x1 = x
      y1 = y
      }
  override func move(direction: String, x: x1, y: y1) {
    switch direction {
      case "Up":
      ++y1
      case "Down":
      --y1
      case "Left":
      --x1
      case "Right":
      --x1
      default:
      break
    }
  }
}
// Enter your code below

2 Answers

jcorum
jcorum
71,830 Points
jcorum
jcorum
71,830 Points

Junaid, good start, but as you saw there are some problems. First, you did too much work. You don't need the member variables in Robot, or the initializer. What variables are needed are inherited from Machine. And the default member-wise initializer works fine.

Second, in the overridden function you only need one parameter: direction.

Third, in the switch statement you need to reference the x and y variables of the Point object location, and increment them correctly. Increment should be in the form x++ or x--, not ++x or --x. With these changes you get:

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
    }
  }
}

Hope this helps.