Swift 函數使用方法

說明：func 聲明一個函數， ->用來分隔函數參數和返回值

//demo1  返回不同類型的值

func greet(name: String,what: String ) -> String{

    return "Hello \(name), today is \(what)"

}

let string = greet("zhongkun","wednesday")

println("print: \(string)")

func getGasPrices() ->(Double,Double,Double){

    return (1.1,2.1,3.1)

}

println("getGasPrices: \(getGasPrices())")

//傳入不同的參數

func sumOf(numbers: Int...) -> Int {

    var sum = 0

    for number in numbers {

        sum += number

    }

    return sum

}

sumOf()

sumOf(42, 597, 12)

//函數可以嵌套

func returnFifteen() -> Int {

    var y = 10

    func add() {

        y += 5

    }

    add()

    return y

}

returnFifteen()

println("nested Function: \(returnFifteen())");

//返回值類型可以是一個函數

func funcReturnTwo() -> (Int -> Int){

    func addOne(number:Int) -> Int {

        return number+1

    }

    return addOne

}

var addOneResult = funcReturnTwo()

let resultReturn = addOneResult(30)

println("functionReturn:\(resultReturn)")

//函數可以作為另一個函數的參數傳入

func hasAnyMatches(list: Int[], condition: Int -> Bool) -> Bool {

    for item in list {

        if condition(item) {

            return true

        }

    }

    return false

}

func lessThanTen(number: Int) -> Bool {

    return number < 10

}

var numbers = [20, 19, 7, 12]

let resultParamterFunc = hasAnyMatches(numbers, lessThanTen)

println("funcionParamter:\(resultParamterFunc)")

//其他(目前還不太清楚)

numbers.map({

    (number: Int) -> Int in

    let result = 3 * number

    return result

})

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