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iOS Enumerations and Optionals in Swift Introduction to Enumerations Enums and Objects

Carlos Mendez
Carlos Mendez
2,646 Points
Posted by Carlos Mendez
Carlos Mendez
2,646 Points

I am not sure how to increase or decrease the location stored property of the Robot class.

Hi there!

I am blanking out and not sure how to implement the method for Robot using the Enum. I am not really sure how I can add or subtract one to Point by applying each member of the enum.

I tried it with an if statement, which I figured wouldn't work.

Thanks!

test.swift 
class Point {
    var x: Int
    var y: Int

    init(x: Int, y: Int) {
        self.x = x
        self.y = y
    }
}

enum Direction {
    case left
    case right
    case up
    case down
}

class Robot {
    var location: Point

    init() {
        self.location = Point(x: 0, y: 0)
    }

     func move(_ direction: Direction) -> Point {
        switch direction {
        case Direction.down: return Point(x: 0, y: -1)
        case Direction.up: return Point(x: 0, y: 1)
        case Direction.right: return Point(x: 1, y: 0)
        case Direction.left: return Point(x: -1, y: 1)
        }
    }
}

1 Answer

KRIS NIKOLAISEN
KRIS NIKOLAISEN
54,971 Points
KRIS NIKOLAISEN
KRIS NIKOLAISEN
54,971 Points

Some hints:

1) The move function doesn't return anything. It just updates the current location.

2) location.x stores the current x coordinate for Robot. So 

location.x = location.x + 1

or

location.x += 1

would move 1 step to the right.