Question

这是我的代码。基本上当用户首先选择餐饮质量时，无论是罚款（20％），休闲（15％）还是酒吧（11％）。然后，用户将以1-5的比例询问用户的食品质量，服务等。根据他们选择的数量，例如，如果精美的餐厅是5/5那么它将比已经20％百分比（每个数字将有一个选定的值添加到提示）。谁能弄明白发生了什么？或者如果有更好的方法可以做到这一点。

import UIKit

@IBDesignable

class ViewController: UIViewController {



    @IBOutlet weak var billTotal: UITextField!

    var diningValue: Double = 0.0
    @IBAction func toggleFineDining(sender: UIButton) {
        sender.highlighted = sender.selected
        if sender.selected == true{
            diningValue = 0.20
        }
    }
    @IBAction func toggleCasualDining(sender: UIButton) {
        sender.highlighted = sender.selected
        if sender.selected == true{
            diningValue = 0.15
        }
    }
    @IBAction func toggleBartender(sender: UIButton) {
        sender.highlighted = sender.selected
        if sender.selected == true{
            diningValue = 0.11
        }
    }


    @IBOutlet weak var service: UITextField!
    @IBOutlet weak var friendliness: UITextField!
    @IBOutlet weak var foodQuality: UITextField!
    @IBOutlet weak var atmosphere: UITextField!
    @IBOutlet weak var overall: UITextField!
    @IBOutlet weak var recommend: UISwitch!
    @IBOutlet weak var total: UILabel!



    func totalBill(inputArray: [Double], value: Double, recommend: Bool)->Double{

        var array: [Double] = []

        let total = inputArray[0]

        for var i = 1; i < inputArray.count; ++i {

            array.append(inputArray[i] * 0.01)

        }

        let sum = array.reduce(0, combine: +)

        var totalTip = Double()

        if recommend == true{

            totalTip = sum + value

        } else {
            if sum < 0.15 {
                totalTip = 0.15
            } else {
                totalTip = sum + value
            }
        }

        let tipValue = totalTip * total

        return total + tipValue

    }



    @IBAction func calcTotal(sender: AnyObject) {
        var valueList = [String(service.text), String(friendliness.text), String(foodQuality.text), String(atmosphere.text), String(overall.text)]

        let list = doubleArray(valueList)



        print(list)

        let initialTotal = Double(billTotal.text!)

        let total_bill = totalBill(list, value: diningValue, recommend: recommend.selected)

        print("Total: ", total_bill)

        print(String(format: "%.3f", Double(total_bill)))

        total.text = "$" + String(format: "%.2f", Double(total_bill))

        //diningValue = diningValue




    }




    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.
    }


}

func doubleArray(list: [String])->[Double]{

    var doubledList: [Double] = []

    for element in 0...list.count{

        let doubledElement = Double(list[element])

        doubledList.append(doubledElement!)

    }

    return doubledList

}

Answer 1

您的问题出在上一个功能中：

func doubleArray(list: [String])->[Double]{

    var doubledList: [Double] = []

    for element in 0...list.count{

        let doubledElement = Double(list[element])

        doubledList.append(doubledElement!)

    }

    return doubledList

}

您的循环正在从0循环到list.count，当list[element]为element list.count时，它会在Out of Index处崩溃

您需要从0...list.count更改为0..<list.count：

func doubleArray(list: [String])->[Double]{

    var doubledList: [Double] = []

    for element in 0..<list.count{

        let doubledElement = Double(list[element])

        doubledList.append(doubledElement!)

    }

    return doubledList

}

我建议你这样做：

func doubleArray(list: [String])->[Double]{

    var doubledList: [Double] = []

    for element in list {
        doubledList.append(Double(element) ?? 0.0)
    }

    return doubledList

}

使用map功能的较短版本：

func doubleArray(list: [String])->[Double]{
    return list.map( { Double($0) ?? 0.0 })
}

创建数组时出现致命错误

1 个答案: