小编Gar*_*Gar的帖子

我是Swift编程的新手,我一直在Xcode 8.2中创建一个简单的tip计算器应用程序,我的计算设置在我的IBAction下面.但是当我实际运行我的应用并输入要计算的金额(例如23.45)时,它会出现超过2个小数位..currency在这种情况下如何格式化？

@IBAction func calculateButtonTapped(_ sender: Any) {

    var tipPercentage: Double {

        if tipAmountSegmentedControl.selectedSegmentIndex == 0 {
            return 0.05
        } else if tipAmountSegmentedControl.selectedSegmentIndex == 1 {
            return 0.10
        } else {
            return 0.2
        }
    }

    let billAmount: Double? = Double(userInputTextField.text!)

    if let billAmount = billAmount {
        let tipAmount = billAmount * tipPercentage
        let totalBillAmount = billAmount + tipAmount

        tipAmountLabel.text = "Tip Amount: $\(tipAmount)"
        totalBillAmountLabel.text = "Total Bill Amount: $\(totalBillAmount)"
    }
}