开始Swift之旅 - HelloWorld

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

import UIKit

var str = "Hello, playground"

print("HelloWorld")
print("hello, swift!")
print("this is my first playground")

一开始就可以看到, Swift和OC还有其他语言的不同之处~没了";"了...接下来就开始学习Swift的更多知识~