Double check your implementation for the Down direction and make sure the location's y property decreases by 1

Question

Can someone help me out with this problem? This code doesn't feel right but works in Xcode. Perhaps I don't understand the question, but I would love some feedback. Thank you!

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 {

    override func move(direction: String) {

        let direction: String = "Up"
            location = Point(x: 0, y: 1)

        switch direction {

        case "Down":
            location = Point(x: 0, y: -1)

        case "Left":
            location = Point(x: -1, y: 0)

        case "Right":
            location = Point(x: 1, y: 0)

        default:
            break
        }
    }
}

Answer 1 · 2016-02-22T02:48:11Z

February 22, 2016 2:48am

Your code is not actually changing the x and y coordinate by 1. You are really just saying that the point is one of four different points: (0, 1), (1, 0), (0, -1), or (-1, 0). You really need to be taking the point of that object and increasing or decreasing either x or y by 1.

Say, for example, you have a Robot object, named robot1. At a certain point in time, robot1's location is set to (4, 3) and you call the func() method and pass in "Left". Your code currently would make the location (-1, 0), when really you want the new location to be (3, 3) (passing "Left" should decrease your x-coordinate by 1).

Your code really needs to be doing things like location.x -= 1 or location.y += 1, depending on what direction is passed into the function.

Hope this helps!

Welcome to the Treehouse Community

Looking to learn something new?

Adam Beck

Adam Beck

Double check your implementation for the Down direction and make sure the location's y property decreases by 1

1 Answer

Keli'i Martin

Keli'i Martin