SwimmingExcercise.swift

struct SwimmingWorkout {
	var distance: Double
	var time: Double
	var stroke: Stroke
	
	static var breaststrokeWorkouts: [SwimmingWorkout] = []
	static var freestyleWorkouts: [SwimmingWorkout] = []
	static var butterflyWorkouts: [SwimmingWorkout] = []
	static var backstrokeWorkouts: [SwimmingWorkout] = []
	
	enum Stroke {
		case freestyle, backstroke, breaststroke, butterfly
	}
	
	func save() {
		switch self.stroke {
		case .freestyle: 
			SwimmingWorkout.freestyleWorkouts.append(self)
		case .butterfly:
			SwimmingWorkout.butterflyWorkouts.append(self)
		case .breaststroke:
			SwimmingWorkout.breaststrokeWorkouts.append(self)
		case .backstroke: 
			SwimmingWorkout.backstrokeWorkouts.append(self)
		}
	}
}

let backstroke1 = SwimmingWorkout(distance: 7.8, time: 4.5, stroke: .backstroke)
backstroke1.save()
print("Add one backstroke exercise: " 
  + String(describing: SwimmingWorkout.backstrokeWorkouts) + "\n\n")

let backstroke2 = SwimmingWorkout(distance: 14, time: 26.2, stroke: .backstroke)
backstroke2.save()
print("Add second backstroke exercise: " 
  + String(describing: SwimmingWorkout.backstrokeWorkouts))