Swift - 26 - 函数的基础写法

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

import UIKit

// 无参无返回
// -> Void可以省略不写, 或者写成(), 因为返回值为空本质是一个空的元组
func run() -> Void // ()
{
    print("I‘m running")
}
run()

// 无参有返回
func sayWelcome() -> String
{
    return "Welcome to play Swift!"
}
print(sayWelcome())

// 有参有返回
func sayHello(name:String?) -> String
{
    let result = "Hello," + (name ?? "Guest") + "!"
    return result
}

var nickName:String?
print(sayHello(nickName))