控制流程 Control Flow

• 左大括號 { 位於同一行尾部且空一格。
• 右大括號 } 位於流程最後。
• 使用明確有意義的單字，避免使用 i, j, k...

For 迴圈

let base = 0
let total = 10

for index in 1...total {

}

let names = ["Anna", "Alex", "Brian", "Jack"]
for name in names {
    print("Hello, \(name)!")
}

While 迴圈

var number = 0
var total = 10
while number < total {

}

條件語句

if

temperatureInFahrenheit = 90

if temperatureInFahrenheit <= 32 {
    print("It's very cold. Consider wearing a scarf.")
} else if temperatureInFahrenheit >= 86 {
    print("It's really warm. Don't forget to wear sunscreen.")
} else {
    print("It's not that cold. Wear a t-shirt.")
}

switch

let someCharacter: Character = "e"

switch someCharacter {
case "a", "e", "i", "o", "u":
    print("\(someCharacter) is a vowel")
case "b", "c", "d", "f", "g", "h", "j", "k", "l", "m",
"n", "p", "q", "r", "s", "t", "v", "w", "x", "y", "z":
    print("\(someCharacter) is a consonant")
default:
    print("\(someCharacter) is not a vowel or a consonant")
}