基本类型

1.整形

var imInt:Int = 80
Int.max//看最大值
Int.min

var imUInt: UInt = 80//无符号整形
UInt.max
UInt.min

let a = 4
let decimalInt:Int = 17
let binaryInt:Int = 0b10001//直接赋二进制值
let octalInt:Int = 0o21//八进制
let hexInt:Int = 0x11//十六进制
let bigunm = 1_000_000//用下划线分割数，分割线不做

2.浮点型

let imFloat:Float = 3.1415926
let imDouble:Double = 3.1415926
let x = 3.1414926
var a = 1.25e10
var b = 1.25e-8
var c = 1_000_000.000_000_1

3.不同类型的运算需要强制类型转换/**/swift语言是一种强类型的语言

let x:Int16 = 100
let y:Int8 = 20
let m = x + Int16(y)
let n = Int8(x) + y

4.布尔值//整形（1）不能代表布尔值，表达式（a==2）可以

let imTrue:Bool = true
let imFalse = false
if imTrue{
    print("I'm true")
}
else{
    print("I'm false")
}

5.元祖tuple

var point = (4, 3)
var httpResponse = (404, "Not Found")
var point2:(Int, Int, Int) = (1, 3, 44)
var httpResponse2:(Int, String) = (11, "hello")
let(x, y) = point
x
y
let(statusCode, statusMessage) = httpResponse
statusCode
statusMessage
point.0
point.1

let point3 = (x:3, y:2)//为元祖的每一个元素定义一个名字
point3.x
point3.y
let point4:(x:Int, y:Int) = (10, 2)
point4.x
point4.y

let loginResult = (true, "login")
let (isLoginSuccess, _) = loginResult//用下划线_忽略一些值
if isLoginSuccess{
    print("login success")
}else{
    print("login failed")
}

var 名字 = "shenlulu"//可以用汉字，表情😊图作为变量名
var 😊 = "smile"
print(名字 + 😊)
//print的特性
let x = 1, y = 2, z = 3, b = true
print(x, y, z, b)//1 2 3 true
print(x, y, z, separator:",")//1,2,3//换行
print(x, y, z, separator:",", terminator:"😊")//1,2,3😊//不换行
print(y, "*", z, "=", y*z)//2 * 3 = 6
print("\(y) * \(z) = \(y*z)")//2 * 3 = 6