swift struct class 스위프트 구조체 클래스 value type reference type

//Object Oriented Programming 객체지향 프로그래밍

//Class와 Structure

struct Resolution {

    var width = 5

    var height = 10

}

var resolution1 = Resolution()

resolution1.height

resolution1.width

var resolution2 = Resolution()

resolution2.height = 30

resolution2.width = 15

class VideoMode {

    var resolution = Resolution()

    var frameRate = 0.0

    var name = ""

}

let videoMode = VideoMode()

videoMode.frameRate

videoMode.name

videoMode.resolution.height

// Value Type vs Reference Type

// struct     vs class

let hd = Resolution(width: 1920, height: 1080)

var cinema = hd

cinema.width = 2048

hd.width // 1920

cinema.width // 2048

let tenEighty = VideoMode()

tenEighty.resolution = hd

tenEighty.name = "1080i"

tenEighty.frameRate = 25.0

let anotherTenEighty = tenEighty

anotherTenEighty.frameRate = 30

tenEighty.frameRate // 30

// Stored Property (값이 저장되어 있는 프로퍼티)

struct FixedLengthRange {

    var firstValue: Int

    let length: Int

}

var rangeOfThreeItems = FixedLengthRange(firstValue: 0, length: 3)

rangeOfThreeItems.firstValue = 6

let rangeOfFourItems = FixedLengthRange(firstValue: 0, length: 4)

//rangeOfFourItems.firstValue = 6  // 값을 바꿀 수 없다고 에러 발생

// Computed Property (값을 저장하지 않고 매번 새로운 값을 개선하는 프로퍼티)

struct Point {

    var x = 0.0

    var y = 0.0

}

struct Size {

    var width = 0.0

    var height = 0.0

}

struct Rect {

    var origin = Point()

    var size = Size()

    var center: Point {

        get {

            let centerX = origin.x + (size.width / 2)

            let centerY = origin.y + (size.height / 2)

            return Point(x: centerX, y: centerY)

        }

        set(newCenter) {

            origin.x = newCenter.x - (size.width / 2)

            origin.y = newCenter.y - (size.height / 2)

        }

    }

}

var square = Rect(origin: Point(x: 0.0, y: 0.0), size: Size(width: 10, height: 10))

let initialCenter = square.center

square.center = Point(x: 15.0, y: 15.0)

square.origin

// Type Property ( 인스턴스에 귀속되어 있지 않고 타입 자체에 연관되어 있는 프로퍼티)