Basic: error in swift code but cannot find out why
<p>hi i am very new to swift coding language and i am learning a tutorial now. 
i am running a tip calculator course from udemy.</p>

<p>as far as i can see i have the same code the teacher is using but this course is from ios 8 early 9 times i do not know if the swift or xcode language changed over time . </p>

<p>this is my code. </p>

<p><div class="snippet" data-lang="js" data-hide="false" data-console="true" data-babel="false">
<div class="snippet-code">
<pre class="snippet-code-html lang-html prettyprint-override"><code>import UIKit

class ViewController: UIViewController {

    
    @IBOutlet weak var txtmaelcost: UITextField!
    @IBOutlet weak var txtTip: UITextField!
    
        @IBOutlet weak var lblTipcalculated: UILabel!
    
    var mealCost = ""
    var tipPercentage = ""
    var awnser : Float = 0
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
    @IBAction func btnCalculate(_ sender: UIButton) {
    calculateTip()
    
    }
    
    @IBAction func btnClear(_ sender: UIButton) {
    }
  
    func calculateTip() -&gt; Bool {
        tipPercentage = txtTip.text!
        mealCost = txtmaelcost.text!
        
        let fMealCost = (mealCost as NSString).floatValue
        let fTipprecentage = (tipPercentage as NSString).floatValue
        
        awnser = fMealCost * (fTipprecentage * 0.01)
        
        lblTipcalculated.text = "(awnser)"
    return true
    }

}</code></pre>
</div>
</div>
</p>

<p>now my error is in the middle   calculateTip()
it says (Result of call calculateTip() is unused ) </p>

<p>i bet this is a easy fix for some of you, but i am unable to figuring out why this is going wrong. </p>

<p>if anyone needs any additional information please ask me.</p>