基础语法

if-else

let age =4

for(区间)

let rang = ...10
rang.contains(11) //false
rang.contains(6) ..ture

带间隔的区间值

for tickMark in stride(form: 4, through: 11, by: 12){
printf(tickMark)
} // 4, 6, 8, 10

switch

switch num {
case 1:
printf(num)
fallthrough
case 2: printf(num)
default:
break
}
case, default后面至少要有一条语句

where

var number = [10, -10, -20, 20, 30, -30]
var sum
for num in number where num >0 {
sum += num
}
print(sum) //60

标签语句

outer: for i in 1...4{
for k in 1...4{
if i == 3 {
break outer
}
if k == 3 {
continue outer
}
printf (@"i = /(i), k = /(k)")
}
}

可变参数

func sum(_ numbers: Int...) ->Int{
var totaol
}

嵌套函数

func forward(_ forward: Boot) -> (Int) -> Int {
func next(_ input: Int) -> Int {
input + 1
}
func previous(_ input: Int) -> Int {
input -1
}
return forward?next:previous
}
forward(true)(3) //4
forward(false)(3) //2