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4,844 PointsChallenge Task 1 of Enumeration and Options, can someone help?
In the editor below you have two objects - classes named Point and Robot. The Robot stores its location as a point instance and contains a move function.
The task of this challenge is to complete the implementation for move. Move takes a parameter of type Direction which is an enumeration listing the possible movement directions.
When you tell the robot to move up (by specifying Direction.Up as the argument), the y coordinate should increase by 1. Similarly moving down means the y coordinate decreases by 1, moving right means the x coordinate increases by 1 and finally left means x decreases by 1.
here is my code it seems alright in Xcode but I could spot the mistake, can someone plz help!
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) {
switch direction {
case .up: location.y += 1
case .down: location.y -= 1
case .right: location.x += 1
case .left: location.x -= 1
}
}
}
3 Answers
Jeff McDivitt
23,970 PointsIt look as though you altered the code that was given in the challenge
You have
func move(direction: Direction) {
switch direction {
case .up: location.y += 1
case .down: location.y -= 1
case .right: location.x += 1
case .left: location.x -= 1
}
}
}
should be
//Do not remove the underscore in front of direction
func move( _ direction: Direction) {
switch direction {
case .up: location.y += 1
case .down: location.y -= 1
case .right: location.x += 1
case .left: location.x -= 1
}
}
}
Jeff McDivitt
23,970 PointsAn underscore tells Swift that the parameter should have no label when called
Example
func add( _ x: Int, _ y: Int {
}
When you call the function you will not need to include the labels x and y
let myAdd = add(1,2)
tangtai chen
4,844 Pointsgot it thx
Aaryen Singh
1,688 PointsCool thx.
tangtai chen
4,844 Pointstangtai chen
4,844 Pointsthx it worked? what does the underscore do in the code anyways? in some challenges I removed the underscore of the code it worked