swift基础

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: 2){
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 k == 3 {
continue outer
}
if i == 3 {
break outer
}
print("i =", i, "k =", k)
}
}
/i = 1 k = 1
i = 1 k = 2
i = 2 k = 1
i = 2 k = 2/

可变参数

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

嵌套函数

//func forward(_ forward: Bool) -> (Int) -> Int {
// func next(_ input: Int) -> Int {
// return input + 1
// }
// func previous(_ input: Int) -> Int {
// return input - 1
// }
// return forward?next:previous
//}
//
//let m = forward(10)(3)
//forward(true)(3) //4
//forward(false)(3) //2