Swift 2 学习笔记 1.基本类型

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基本类型

• 常量、变量和声明

let num = 9 // 常量
var index = 3 // 变量
let str: String = "Hello" // 类型声明

• 整型

let aInt: Int = 8  // 整型
let aUInt: UInt = 90  // 无符号整型

• 浮点数和类型转换

let aFlort: Float = 3.1415926  // 3.141593
let aDouble: Double = 3.1415926  // 3.1415926

let x: UInt16 = 100
let y: UInt8 = 8
let m = x + UInt16(y)  // 108

• 布尔类型和简单的if语句

let aTure = true
let aFalse: Bool = false

if aTure {
    print("true")
}else {
    print("false")
}

• 元组(Tuple)

let point = (2,3)
point.0  // 2
point.1  // 3

let point2 = (x: 4, y: 1)
point2.x  // 4
point2.y  // 1

let point3: (x: Int, y: Int) = (5,4)
point3.x  // 5
point3.y  // 4

let httpRespense: (Int, String) = (200,"OK")
let (statusCode, _) = httpRespense
statusCode  // 200

• 其他(变量名、print和注释)

let name = "Owen"
print("Hello, \(name)")  // Hello,Owen
/*
多行注释
*/