[swift] code log, day 1

iBooks 의 SWIFT 4를 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 1

//: Playground - noun: a place where people can play

import UIKit

//Simple Values

//decraring variables

var str = "Hello, playground"

let implictInteger = 80

let explicit:Double = 80

let explicit1: Float = 80

let label = "the width is"

let width = 83

let widthLabel = label + String(width)

print("hello world")

let apples = 3

let oranges = 4

let applesSummary = "I have \(8.0) apples"

let fruitSummary = "I have \(8.0 + 10.0) pieces of fruit"

//array and dictionary

var shoppingList = ["catfish", "water", "tulips", "blue paint"]

shoppingList[1] = "bottle of water"

var occupations = [

    "Malcolm" : "Captain",

    "Kaylee" : "Mechanic",

]

occupations["Jayne"] = "Public Relations"

let emptyArray = [String]()

let emptyDictionary = [String:Float]()

//Control Flow

//for loop & if else

let individualScores = [12, 14, 25, 34, 134]

var teamScore = 0

for score in individualScores {

    if score > 30 {

        teamScore+=3

    } else {

        teamScore+=1

    }

}

print(teamScore)

//optional variable

var optionalString: String? = "Hello"

print(optionalString == nil)

var optionalName: String? = "John Appleseed"

var greeting = "Hello!"

if let name = optionalName {

    greeting = "hello, \(name)"

}

let nickName: String? = nil

let fullName: String = "John Appleseed"

let informalGreeting = "Hi \(nickName ?? fullName)"

//switch

let vegetable = "red pepper"

switch vegetable{

case "celery":

    print("wawa")

case "cucumber", "watercress":

    print("wwwwww")

case let x where x.hasSuffix("pepper"):

    print("wow found red pepper")

default:

    print("default")

}

//dictionary

let interestingNumbers = [

    "prime":[2,3,5,7,11,13],

    "fibonacci":[1,1,2,3,5,8],

    "square":[1,4,9,16,25],

]

var largest = 0

for (kind, numbers) in interestingNumbers {

    for number in numbers {

        if number > largest {

            largest = number

        }

        print(kind + ":" + String(largest))

    }

}

print(largest)

//while

var n=2

while n<100 {

    n *= 2

}

print(n)

var m = 2

repeat {

    m *= 2

} while m < 100

print (m)

// range

var total = 0

// .. vs =< ...

for i in 0..<4 {

    total += i

    print (total)

}

print (total)

//function and Closure

//function

func greet(person: String, day: String) -> String {

    return "Hello \(person), Today is \(day)."

}

greet(person: "Bob", day: "Friday")

func greetWithSpecial(person: String, special: String)->String{

    return "Hello \(person), Today's Lunch Special is \(special)."

}

greetWithSpecial(person: "Mike", special: "Meat Balls")

// _ <-- 추가 하여 함수 호출 시 argument label 를 쓰지 않게 한다.

func greet(_ person: String, day: String) -> String {

    return "Hello \(person), Today is \(day)."

}

greet("Sam", day: "Saturday")

//tuple , returns multiple results

func calculateStatistics(scores:[Int]) -> (min: Int, max: Int, sum: Int){

    var min = scores[0]

    var max = scores[0]

    var sum = 0

    

    for score in scores {

        

        if score > max {

            max = score

        } else if score < min {

            min = score

        }

        sum += score

    }

    return (min, max, sum)

}

let statistics = calculateStatistics(scores: [1,2,3,4,5,6,7,8,9,10])

print(statistics.min)

print(statistics.max)

print(statistics.sum)

print(statistics.0)

print(statistics.1)

print(statistics.2)

func sumOf(numbers: Int...)-> Int {

    var sum = 0

    for number in numbers {

        sum += number

    }

    return sum

}

sumOf()

sumOf(numbers: 1,2,3,4,5,6,7,8,9,10)

//experiment

func averageOf(numbers: Double...)-> Double{

    var average : Double = 0.0

    var counter : Double = 0.0

    var sum : Double = 0.0

    

    for number in numbers {

        sum += number

        counter += 1.0

    }

    if counter != 0.0 {

        average = sum / counter

    } else {

        average = 0.0

    }

    

    print("Sum = \(sum)")

    print("counter = \(counter)")

        

    return average

}

averageOf()

averageOf(numbers: 1,2,3,4,5,6,7,8,9,10)

func returnFifteen() -> Int{

    var y = 10

    

    func add(){

        y+=5

    }

    add()

    return y

}

returnFifteen()