函式整理比較

無參數函式（Functions Without Parameters）

func sayA(){
    print("歡迎光臨~")
    print("今天有特價活動哦！")
}
sayA()

函式：單一參數函式

func sayB(words: String) {
    print("hi, \(words)!")
}
sayB(words: "歡迎光臨B")
sayB(words: "今天有特價活動哦！B")

函式：多參數函式

func sayC(word1:String, word2:String){
    print("hi, \(word1),\(word2)")
}
sayC(word1: "歡迎光臨C", word2: "今天有特價活動哦！C")

函式：有回傳值的函式

func add(word1:String, word2:String) -> String{
    //->代表執行完函式之後，回傳值的型別是String
    return word1 + word2
}

let sayD = add(word1: "歡迎光臨D", word2: "今天有特價活動哦！D")
print("hi, \(sayD)")