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# Looking for Explanation

Hey guys,

Just kind of confused and wanted to clarify. Does "switch" mean you're switching the constraint (direction) for the result of each case? If not, what's an easy description on how to understand what a switch is?

Secondly, what's the reasoning behind using location.y instead of Point.y for example?

classes.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) {
switch direction {
case .Left: location.x -= 1
case .Right: location.x += 1
case .Up: location.y += 1
case .Down: location.y -= 1

}
}
```

Paul, just noticed you have a missing closing curly brace:

```    func move(direction: Direction) {
switch direction {
case .Left: location.x -= 1
case .Right: location.x += 1
case .Up: location.y += 1
case .Down: location.y -= 1
}  //missing
}
```

The function takes one parameter, a direction. Think of switch as a shorthand way of writing if...else if...else... statements. Thinking this way, the first case says: if direction is Left, then do something. The second case says: else if direction is Right, then do something different.

In each case, what is done is either the x or y value of location (which is a Point) is incremented or decremented.

Hi Paul,

A 'switch' statement checks a variable and then directs the flow to the relevant code. As in real life, when a train arrives at a switch based upon what train it is, it is then directed to the relevant track (I know nothing of trains so forgive my ignorance train lovers ;).

Another way to think of a switch (thought much messier) is using if statements, else if, else if etc.

Location is created as a variable of method Point, so using Point.y wouldn't make sense. When you set Location = Point(x:0, y:0), you are saying set Location to a Point object with x=0 and y=0.