[Swift] function 1-4

import Foundation

func joinString(#strings: [String]) -> String {

    var returnStr = ""

    for str in strings {

        returnStr += str

    }

    return returnStr

}

func joinString(#strings: String...)->String{

    return joinString(strings: strings)

}

var arrayOfStrings = ["I", "am", "an", "Array"]

joinString(strings: arrayOfStrings)

joinString(strings: "I", "am", "variadic")

func incrementNumnber(inout #number: Int, increment: Int = 1){

    number += increment

}

var ourInt = 1

incrementNumnber(number: &ourInt)

ourInt

incrementNumnber(number: &ourInt, increment: 10)

ourInt