/* イニシャライザ */ struct Color { // let red = 0.0, green = 0.0, blue = 0.0 // error: immutable value 'self.red' may only be initialized once let red, green, blue : Double init(red: Double, green: Double, blue: Double) { self.red = red self.green = green self.blue = blue } } let magenta = Color(red: 1.0, green: 0.0, blue: 1.0)