После запуска кода выдает ошибку и программа падает

После запуска кода из storyboard при введении значений в текстовое поле выдает ошибку: Terminating app due to uncaught exception NSInvalidArgumentException', reason: '-[MedicalCalc.ViewController heightField:]: unrecognized selector sent to instance 0x7f7be1f0dab0 Вот код: '''

import UIKit

class ViewController: UIViewController {

    @IBOutlet weak var heightField: UITextField!
    
    @IBOutlet weak var weightField: UITextField!
    
    @IBOutlet weak var resultHiddenTextCiklopf: UILabel!
    
    @IBOutlet weak var resultHiddenTextDoks: UILabel!
    
    
    @IBOutlet weak var resultMassIndex: UILabel!
    
    func squareBody(heightBody: Double, weightBody: Double) -> Double {
        let squareBodyMath = 0.0167 * pow(heightBody, 0.5) * pow(weightBody, 0.5)
        return squareBodyMath
    }
    
    let doksorubicin: Double = 60.0
    
    let ciklophosfamid: Double = 600.0
    
    
    @IBAction func button(_ sender: Any) {
        let height = Double(heightField.text!)
        let weight = Double(weightField.text!)
        let resultSquareBody = squareBody(heightBody: height!, weightBody: weight!)
        let formatResultSquareBody = String(format: "%.2f", resultSquareBody)
        let doksorubicinDose = doksorubicin * resultSquareBody
        let ciklophosfamidDose = ciklophosfamid * resultSquareBody
        let resultingCikloph = String (format: "%.0f", ciklophosfamidDose)
        let resultingDoks = String (format: "%.0f", doksorubicinDose)
        
        print(resultingCikloph)
        
        print(resultingDoks)
        
        print(formatResultSquareBody)
        
        resultHiddenTextDoks.text = resultingDoks
        
        resultHiddenTextCiklopf.text = resultingCikloph
        
        resultMassIndex.text = formatResultSquareBody

    }
    
    
    
}

''' Подскажите, пожалуйста, как исправить.