ios - Linker error in Xcode? -

When I try to run my app on the simulator I'm getting a strange error. Error within the following address / file (I'm unsure about, it is said):

  undefined symbols of architecture i386: " _main ", refers to the main entrance of the underlying entry / start executable LD: the architecture was not a symbol for I386 clang: error: linker command failure code use -V fail to see (charged with 1)  

The above error has two parts. They are highlighted in red; Referenced from "_ main",: and linker failed with command failure code 1 (Use -V to view invitation) .

I have never been able to fix it before the error has happened. Here in my code is required:

  class ViewController: UIViewController {viewDidLoad () {super.viewDidLoad function overrides ()} override function didReceiveMemoryWarning () {super.didReceiveMemoryWarning ()} @ Aibiotlet Weaker warfare value: UILBL! @Iboutlet weak var strInputField: UITextField! Funk Textfield Shawled Retron (Textfield: UITFixified) - & gt; Bool {textField.resignFirstResponder () words = textField.text's score = Scorford (words) return true} var Tekstfild: UITextField! Private word alphabet = [ "A", "B", "C", "D", "E", "F", "G", "H", "I", "J", "", " L "," m "," n "," o "," p "," q "," r "," s "," t "," u "," v "," w "," x " , "Y", "z"] func valueOfLetter (letter: character) - & gt; Int {LetterString = String (letter) .uppercaseString Index = Address (Alphabet, LetterString) Return Index! = Zero? Index! + 1: 0 Function score foreordord (word: string) - & gt; Int {go characters = array (word) return letters.reduce (0) {Yoga, letter in yoga + self.valueOfLetter (letter)}} function text field (field: UITextField, shouldChangeCharactersInRange Range: NSRange, replacementString string: string) - & Gt; Bull Know {go currentWord = textField.text as a NSString NewWord = currentWord.stringByReplacingCharactersInRange (range, withString: string) a score of score = scoreForWord (newWord) true return}}  

Include what this means (error).

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This error message is already done shortly before the month of me. Your library is not supported for the simulator, you need to run on the actual device instead of the simulator.