iBooks 의 SWIFT 4 를 통해 언어 공부 중입니다. 이때 사용된 책 속의 코드 및 연습문제 등의 코드 로그입니다.
아래 코드들은 Github 에서도 다운받을 수 있습니다.
SWIFT_Playground_Excersice: https://github.com/youp-han/SWIFT_Playground_Excersice
//------------------------------------------------------------
// 코드 로그 입니다.
// Day 4
// Enumerationas and Structures
// Default 로 raw value 는 0 에서 시작하지만, 다음의 경우
// case ace = 1에서 시작함.
enum Rank: Int{
case ace = 1
case two, three, four, five, six, seven, eight, nine, ten
case jack, queen, king
func simpleDescription() -> String{
switch self{
case .ace:
return "ace"
case .jack:
return "jack"
case .queen:
return "queen"
case .king:
return "king"
default:
return String(self.rawValue)
}
}
}
let ace = Rank.ace
let aceRawValue = ace.rawValue
let two = Rank.two
let twoRawValue = two.rawValue
if let convertedRank = Rank(rawValue:3) {
let threeDescription = convertedRank.simpleDescription()
print(threeDescription)
}
//enum 2
enum Suit{
case spades, hearts, diamonds, clubs
func simpleDescription()->String{
switch self{
case .spades:
return "spades"
case .hearts:
return "hearts"
case .diamonds:
return "diamonds"
case .clubs:
return "clubs"
}
}
//experiment
func color()->String{
switch self{
case .spades:
return "black"
case .clubs:
return "black"
default:
return "red"
}
}
}
let hearts = Suit.hearts
let heartsDescription = hearts.simpleDescription()
let heartsColor = hearts.color()
// enum 3
enum ServerResponse {
case result (String, String)
case failure (String)
}
let success = ServerResponse.result("6:00 am", "8:09 pm")
let failure = ServerResponse.failure("Out of cheese")
switch success {
case let .result(sunrise, sunset):
print("Sunrise is at\(sunrise) and sunset is at \(sunset).")
case let .failure(message):
print("Failure... \(message)")
}
//struct
// struct vs class
// struct gets copied where classes are passed by reference
struct Card {
var rank: Rank
var suit: Suit
func simpleDescription() -> String {
return "The \(rank.simpleDescription()) of \(suit.simpleDescription())"
}
}
let threeOfSpades = Card(rank: .three, suit: .spades)
let threeOfSpedesDescription = threeOfSpades.simpleDescription()
//Protocals and Estensions
//Classes, enum and Structs can adopt protocols
protocol ExampleProtocol {
var simpleDescription : String { get }
mutating func adjust()
}
class SimpleClass: ExampleProtocol{
var simpleDescription: String = "A very simple class"
var anotherProperty: Int = 52342
func adjust(){
simpleDescription += " Now 100% adjusted"
}
}
var a = SimpleClass()
a.adjust()
let aDescription = a.simpleDescription
struct SimpleStruture: ExampleProtocol {
var simpleDescription: String = "A simple structure"
mutating func adjust(){
simpleDescription += " (adjusted)"
}
}
var b = SimpleStruture()
b.adjust()
let bDescription = b.simpleDescription
// why mutating func in Structure?
// because, the structure is a value type where class is a reference type
// and to make changes in a function of the structure,
// the function should be mutable
// example
struct Rectangle {
var height = 1
var width = 1
func area() -> Int{
return height * width
}
mutating func scaleBy(value: Int) {
width*=value
height*=value
}
}
var rect = Rectangle()
// let rect = Rectangle() will give errors for its a value type (immutable)
rect.area()
rect.scaleBy(value: 3)
rect.area()
// extension of protocol
extension Int: ExampleProtocol {
var simpleDescription: String {
return "the number \(self)"
}
mutating func adjust(){
self += 42
}
}
print (7.simpleDescription)
let protocolValue: ExampleProtocol = a
print(protocolValue.simpleDescription)
//print(protocolValue.anotherProperty)
//Error Handling
enum PrinterError: Error{
case outOfPaper
case noToner
case onFire
}
func send(job: Int, toPrinter printerName: String) throws -> String{
if printerName == "Never Has Toner" {
throw PrinterError.noToner
}
return "Job Sent"
}
do{
// the following statement throws no error
// let printerResponse = try send(job: 1040, toPrinter: "Bi Sheng")
let printerResponse = try send(job: 1040, toPrinter: "Never Has Toner")
print(printerResponse)
}catch{
print(error)
}
