swift - Print evens app error help - cannot convert to type string -

i've been trying take number , display of numbers said number in string. currently, think have working i'm having trouble getting display in label.

the error i'm getting on: label.text = factor. error states: "cannot assign value of type '()' type 'string?'

i wonder if had idea how fix or improve code , explain did wrong? i'm still kind of new swift.

here's code:

import uikit  class viewcontroller: uiviewcontroller {  @iboutlet var input1 : uitextfield! @iboutlet var label : uilabel!  @ibaction func factoraction(sender: uibutton) {     if let text = input1.text {         if let num = int(text) {             // text int             let factor = getevens(<#t##input: int##int#>)             label.text = factor         } else {             // show user entered text isn't number         }     } else {         // there's no text     } } // notifies user when no text or if non number string/whole integer has been entered. // recycled code factor application because useful   func getevens(_ input: int){     var output: string = ""     in 0 ... input {         if (i % 2 == 0){             output += string(i) + ","         }     }     output.remove(at: output.index(before: output.endindex))     print(output); }    // returns result  override func viewdidload() {     super.viewdidload()     // additional setup after loading view, typically nib. }  override func didreceivememorywarning() {     super.didreceivememorywarning()     // dispose of resources can recreated. } 

}

thanks again guys!

edit 2: went ahead , updated code; i'm getting thread 1: breakpoint 1.1 whenever try , enter number textbox when testing app. ideas why happening?

import uikit  class viewcontroller: uiviewcontroller { @iboutlet weak var input1 : uitextfield! @iboutlet weak var label : uilabel!  @ibaction func factoraction(sender: uibutton) {     if let text = input1.text {         if let num = int(text) {             // text int             let factor = getevens(num)             label.text = factor         } else {             // show user entered text isn't number         }     } else {         // there's no text     } }  // notifies user when no text or if non number string/whole integer has been entered. // recycled code factor application because useful  func getevens(_ input: int) -> string {     let output = stride(from: 0, through: input, by: 2)         .map(string.init)         .joined(separator: ",")     return output }  override func viewdidload() {     super.viewdidload()     // additional setup after loading view, typically nib. } } 

your getevens() function prints string console, not return anything. (more precisely, return type void or (), , type '()' in error message

"cannot assign value of type '()' type 'string?'

comes from.)

what want

func getevens(_ input: int) -> string { // <-- return type `string`     var output: string = ""     in 0 ... input {         if (i % 2 == 0){             output += string(i) + ","         }     }     output.remove(at: output.index(before: output.endindex))     return output // <-- returned value } 

note can achieve same result with

func getevens(_ input: int) -> string {     let output = stride(from: 0, through: input, by: 2)         .map(string.init)         .joined(separator: ",")     return output } 

which may bit more "swifty":

• stride(from: 0, through: input, by: 2) gives sequence of numbers 0 input,
• map(string.init) converts each number string, and
• joined(separator: ",") concatenates results single string, adding comma between elements.