title: How to convert textField.text value to Integer and sum two Integers
body: <blockquote>
    <p>Initialization of immutable value 'textfieldInt' was never used;
    consider replacing with assignment to '_' or removing it  and
    textfield2Int</p>
  </blockquote>
  
  <p>I get that warning twice for textfieldInt</p>
  
  <p>This is all the code I have: </p>
  
  <pre><code>class ViewController: UIViewController {
  
      @IBOutlet weak var textField1: UITextField!
      @IBOutlet weak var textField2: UITextField!
      @IBOutlet weak var output: UILabel!
  
      @IBAction func calculate(_ sender: AnyObject) {
          let textfieldInt: Int? = Int(textField1.text!)
          let textfield2Int: Int? = Int(textField2.text!)
          let convert = textField1.text! + textField2.text!
          let convertText = String(convert)
          output.text = convertText
  
  }
  </code></pre>