swift 单例的实现方法及实例

public class Game {

  public var score = 0

  public static let dafaultGame = Game()

  private init(){

  }

  public func addscore(){

    score += 10
  }
}

let game1 = Game.dafaultGame
game1.addscore()
game1.score

let game2 = Game.dafaultGame
game2.addscore()
game2.score