Bài 18: Methods trong swift – Lập trình Swift cơ bản

let counter = Counter()

// the initial counter value is 0

counter.increment()

// the counter's value is now 1

counter.increment(by: 5)

// the counter's value is now 6

counter.reset()

func increment() {

   self.count += 1

}

struct Point {  
  var x = 0.0, 
  y = 0.0 

  func isToTheRightOf(x: Double) -> Bool {     
      return self.x > x   }
  }

  let somePoint = Point(x: 4.0, y: 5.0)if somePoint.isToTheRightOf(x: 1.0) {

      print("This point is to the right of the line where x == 1.0")

  }// Prints "This point is to the right of the line where x == 1.0"
}

struct Point {

   var x = 0.0, y = 0.0

   mutating func moveBy(x deltaX: Double, y deltaY: Double) {

       x += deltaX

       y += deltaY

   }

}

var somePoint = Point(x: 1.0, y: 1.0)

somePoint.moveBy(x: 2.0, y: 3.0)

print("The point is now at (\(somePoint.x), \(somePoint.y))")

let fixedPoint = Point(x: 3.0, y: 3.0)

fixedPoint.moveBy(x: 2.0, y: 3.0)

enum TriStateSwitch {

   case off, low, high

   mutating func next() {

       switch self {

       case .off:

           self = .low

       case .low:

           self = .high

       case .high:

           self = .off

       }

   }

}

var ovenLight = TriStateSwitch.low

ovenLight.next()

// ovenLight is now equal to .high

ovenLight.next()

// ovenLight is now equal to .off

class SomeClass {

   class func someTypeMethod() {

       // type method implementation goes here

   }

}

SomeClass.someTypeMethod()

struct LevelTracker {
   static var highestUnlockedLevel = 1
   var currentLevel = 1
   static func unlock(_ level: Int) {
       if level > highestUnlockedLevel { highestUnlockedLevel = level }
   }
   static func isUnlocked(_ level: Int) -> Bool {
       return level <= highestUnlockedLevel
   }
   @discardableResult
   mutating func advance(to level: Int) -> Bool {
       if LevelTracker.isUnlocked(level) {
           currentLevel = level
           return true
       } else {
           return false
       }
   }
}

class Player {
   var tracker = LevelTracker()
   let playerName: String
   func complete(level: Int) {
       LevelTracker.unlock(level + 1)
       tracker.advance(to: level + 1)
   }
   init(name: String) {
       playerName = name
   }
}

var player = Player(name: "Argyrios")

player.complete(level: 1)

print("highest unlocked level is now \(LevelTracker.highestUnlockedLevel)")

// Prints "highest unlocked level is now 2"

player = Player(name: "Beto")
if player.tracker.advance(to: 6) {
   print("player is now on level 6")
} else {
   print("level 6 has not yet been unlocked")
}
// Prints "level 6 has not yet been unlocked"