如何在Swift 4.2中制作EMI计算器

Question

import UIKit

class EMIVC: UIViewController {

    @IBOutlet weak var amounttxt : UITextField!
    @IBOutlet weak var yesrMonthtxt :UITextField!
    @IBOutlet weak var interestRateTxt : UITextField!
    @IBOutlet weak var resultTxt :UITextField!

    var model : EMIModel?
    //var logic : EMICalculate?
   var res : String?
   // var p : Double = 100000
    //var r : Float = 8.25
    //var t : Double = 2

//    /*
//     r = r / (12 * 100); // one month interest
//     t = t * 12; // one month period
//     emi = (p * r * pow(1 + r, t)) / (pow(1 + r, t) - 1);
//     */
//
    override func viewDidLoad() {
        super.viewDidLoad()



      //print(res)
        // Do any additional setup after loading the view.
    }

    @IBAction func resultShow(_ sender: UIButton){
        display_Somthing()
      //resultTxt.text = "\(res)"

    }


    func display_Somthing()  {

//        let formatter = NumberFormatter()
//        formatter.locale = Locale.current
//        // Change this to another locale if you want to force a specific locale, otherwise this is redundant as the current locale is the default already
//        formatter.numberStyle = .currency
//
//        self.amounttxt.text = formatter.string(from: NSNumber(value: (model?.amount.isNaN)! ? 0 : (model?.amount)!))
//        self.interestRateTxt.text = formatter.string(from: NSNumber(value: (model?.interest.isNaN)! ? 0 : (model?.interest)!))
//        self.yesrMonthtxt.text = formatter.string(from: NSNumber(value: (model?.tenure.isNaN)! ? 0 : (model?.tenure)!))

        guard let loan_amount = amounttxt.text else {return}
        guard let interest_Rate = interestRateTxt.text else {return}
        guard let tenure = yesrMonthtxt.text else {return}
       // guard var res = resultTxt.text else {return}

        model?.setEMI(amount: Double(loan_amount)!, interest: Double(Float(interest_Rate)!), tenure: Double(tenure)!)

      res = calculateEmi(p: (model?.amount)!, t: (model?.tenure)!, r: (model?.interest)!)
        //resultTxt.text = calculateEmi(p: (model?.amount)!, t: (model?.tenure)!, r: (model?.interest)!)
        print(res)
        //resultTxt.text = "\(res)"

    }
    func calculateEmi(p : Double, t : Double, r : Double) -> Double {
        let r = r / 12 / 100
        let t = t * 12
        return p * r / (1 - (pow(1/(1 + r), t)))
    }


}

我有很多时间试图在swift 4.2（ios）中制作EMI计算器，但无法在swift中的代码中了解其制作和实现方式。因此请帮助我了解EMI计算器的代码

我必须取一个文本字段作为本金，然后取另一个文本字段作为利率，然后取下一个分类年n个月，这里无论m生成代码是什么都不取值。