Swift - 06 - 数值类型转换和类型别名

//: Playground - noun: a place where people can play
 
import UIKit
 
var str = "Hello, playground"
 
// 数值类型转换
let three = 3
let PI = Double(three) + 0.1415926    // 两个类型不相同的数值不能进行基础运算,所以进行数值类型转换
 
// 类型别名(typealias)
typealias NSInterger = Int
var number : NSInterger = 10
var count = NSInterger.max