Swift 函数

func test() ->Void{
    print("test")
}

func test() {
    print("test")
}
func test() ->(){
    print("test")
}

func pi() -> Double {
    return 3.14
}

func sum (v1 :Int , v2: Int) -> Int{
    return v1+v2;
}
//形参默认是let 也只能是let
func sum (v1 :Int , v2: Int) -> Int{
     v1+v2;
}

func calcute(v1 :Int , v2: Int) ->(sum:Int,cha:Int,avg:Double){
    return (v1+v2,v1-v2,Double((v1+v2))/2.0)
}

print(calcute(v1: 2, v2: 3))
print(calcute(v1: 2, v2: 3).sum)
print(calcute(v1: 2, v2: 3).cha)
print(calcute(v1: 2, v2: 3).avg)

func gotoWork( time:Int) ->(){
    print("gotoWork:\(time)点")
}
//参数标签
func gotoWork(at time:Int) ->(){
    print("gotoWork:\(time)点")
}

gotoWork(at: 8)
//使用下划线省略参数标签
func sum (_ v1 :Int ,_ v2: Int) -> Int{
    return v1+v2;
}

print(sum(3, 3))

func person (name : String="nobody" , age: Int = 50 ,weight:Double) {
    print("name:\(name)  age\(age)  weight:\(weight)")
}
person(name: "jack", age: 18, weight: 99.5)
person(weight: 33)
person(name: "tom", weight: 12)
// 输出
//name:jack  age18  weight:99.5
//name:nobody  age50  weight:33.0
//name:tom  age50  weight:12.0

func sum (numbers : Int...)->(Int){
    var s = 0
    
    for i in numbers {
        s+=i
    }
    return s
}

print(sum(numbers: 1,2,3,4))  //10
// 注意 一个函数只有有一个可变参数 并且紧跟着的第一个 参数标签不能省略
func test (numbers: Int... , name:String ,_ age :Int){
    print("number:\(numbers) name:\(name) age:\(age)")
}
test(numbers: 1,3,5, name: "jack", 20)
//输出 number:[1, 3, 5] name:jack age:20

/// - Parameters:
///   - items: Zero or more items to print.
///   - separator: A string to print between each item. The default is a single
///     space (`" "`).
///   - terminator: The string to print after all items have been printed. The
///     default is a newline (`"\n"`).
//public func print(_ items: Any..., separator: String = " ", terminator: String = "\n")
// separator 元素分割符  terminator 结尾符号
print(1,2,3,4, separator: "--", terminator: "..")
print(8,9,10, separator: "--", terminator: "..")
//输出 1--2--3--4..8--9--10..