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Start your free trialLorenzo Leva
12,262 PointsSwitch case?
Hi, wondered why my code doesn't work with a switch case but only with an if-else clause. In theory, it should work. Thank you already for your help. Here is my code:
class TemperatureController: UIViewController {
var temperature: Double {
didSet {
switch self {
case let x where x > 40 : view.backgroundColor = .blue
case let x where x < 80 : view.backgroundColor = .red
default: view.backgroundColor = .green
}
}
}
init(temperature: Double) {
self.temperature = temperature
super.init()
}
override func viewDidLoad() {
super.viewDidLoad()
view.backgroundColor = .white
}
}
1 Answer
Steve Hunter
57,712 PointsHi there,
Your errors are:
swift_lint.swift:73:30: error: binary operator '>' cannot be applied to operands of type 'TemperatureController' and 'Int'
case let x where x > 40 : view.backgroundColor = .blue
~ ^ ~~
swift_lint.swift:74:30: error: binary operator '<' cannot be applied to operands of type 'TemperatureController' and 'Int'
case let x where x < 80 : view.backgroundColor = .red
~ ^ ~~
So, you're comparing the wrong thing by just using self
- that refers to the controller, not the member variable. Use self.temperature
for your switch
.
Then, check your logic. You are testing for greater than 40 and less than 80. That's not what the question is looking for.
var temperature: Double {
didSet {
switch self.temperature {
case let x where x < 40 : view.backgroundColor = .blue
case let x where x > 80 : view.backgroundColor = .red
default: view.backgroundColor = .green
}
}
}
Steve.