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

Posted by Saleh Bubishate
Saleh Bubishate
1,613 Points

i got confused with this challenge

How can I increase / decrease x or y coordinates by 1

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.left : return Point(x: -1, y: 0 )
        case Direction.right : return Point (x: 1, y: 0 )
        case Direction.up : return Point(x: 0, y:  1)
        case Direction.down : return  Point(x: 0, y: -1)
        }
    }
}

2 Answers

Magnus Hållberg
Magnus Hållberg
17,232 Points

You are almost there. To increase or decrease these values you use the "location property" with dot notation. Location is an instance of Point witch holds the coordinate values. Like this: 

        switch direction {
        case Direction.left : return location.x -= 1
        case Direction.right : return location.x += 1
        case Direction.up : return location.y += 1
        case Direction.down : return  location.y -= 1
        }
Saleh Bubishate
Saleh Bubishate
1,613 Points

thanks a lot

Saleh Bubishate
Saleh Bubishate
1,613 Points
Saleh Bubishate
Saleh Bubishate
1,613 Points

but how can we return a value without typing a "->" in the instance ?

Magnus Hållberg
Magnus Hållberg
17,232 Points

I'm not sure I understand the question. The method is returning a value of point through the switch, just as specified in the method declaration.