Swift 函数的基本使用

//

//  main.swift

//  testFunctions

//

//  Created by  朱立志 on 14-6-11.

//  Copyright (c) 2014年 zlz. All rights reserved.

//

import Foundation

println("Hello, World!")

//单个参数输入函数

func sayHello(personName : String ) -> String{

    return "hello func "+personName+"!"

}

println(sayHello("zlz"))

// 多个参数传入

func halfOpenRangeLength(start : Int , end : Int ) -> Int{

    return start + end

}

println(halfOpenRangeLength(2,4))

// 没有返回值的函数

func sayGoodBye(personName :String ) {

    println("good bye "+personName)

}

sayGoodBye("zlz")

// 多个返回值函数

func count(inputStr : String) ->(vowels : Int , consonants : Int , others : Int){

    var vowels  = 0 , consonants = 0, others = 0

    for charset in inputStr {

        switch String(charset).lowercaseString {

            case "a","e","i","o":

             ++vowels

            case "b","c","d","f","l","k":

             ++consonants

            default :

            others++

        }

    }

    return (vowels , consonants , others)

}

println(count("abdefiolkzwn"))

// 参数别名 #表示函数参数名和函数内部参数名 // “local parameter name and the external parameter name”

func containsCharacter(#string: String, #characterToFind: Character) ->Bool {

    for character in string {

        if character == characterToFind {

            return true

        }

    }

    return false

}

// 给函数参数定义默认值

func join (string s1: String , toString s2 : String , withJoiner joiner :String = "") ->String{

    return s1+s2+joiner

}

println(join(string :"zhu",toString: " lizhi ",withJoiner:" joiner"))

// 可变参数

func arithmeticMean (numbers : Double ...) -> Double {

    var total:Double =0

    for number in numbers {

        total += number

    }

    return total

}

println(arithmeticMean(3,2,5,7,9,13))

func addTwoInts(a : Int , b : Int)-> Int{

    return a+b

}

var mathFunction : (Int ,Int) ->Int = addTwoInts

println(mathFunction(3,2))

// 函数参数是函数的函数

func printMathResult(mathFunction:(Int,Int) ->Int , a : Int , b :Int){

    println("result\(mathFunction(a,b))")

}

println(printMathResult(mathFunction ,4 , 5))