JAVA向字符串添加double [复制]

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• Convert String to double in Java 12 answers

在Java 12答案中将String转换为double

I just have a question about adding some currency ($) in JAVA, I used the NumberFormat.getCurrencyInstance(); to get my outputs in "$". My program is to input some money (String format) for example the program only accepts ($100.00, $50.00, $20.00 ... and so on) so I used this code:

我刚才有一个关于在JAVA中添加一些货币($)的问题,我使用了NumberFormat.getCurrencyInstance();得到我的输出“$”。我的程序是输入一些钱(字符串格式),例如程序只接受($ 100.00,$ 50.00,$ 20.00 ......等等)所以我使用了这段代码:

String payment = keyboard.next();
while (!(payment.equals("$100.00")) && (!payment.equals("$50.00")) && (!payment.equals("$20.00")) && (!payment.equals("$10.00")) && (!payment.equals("$5.00")) && (!payment.equals("$2.00")) && (!payment.equals("$1.00")) {
System.out.print("Invalid coin or note. Try again. ");
payment = keyboard.next(); }

How can I get the inputs (100.00, 50.00 ... ) as a Double in order to subtract them from the total price.. for example I want (100.00-12.00) (12.00 is the total price)

我怎样才能将输入(100.00,50.00 ......)作为Double来从总价中减去它们...例如我想要(100.00-12.00)(12.00是总价)

Any help would be appreciated Thanks

任何帮助将不胜感激谢谢

2 个解决方案

#1

If your input is a "$" sign, you can delete the first element of your string and then convert it to a double.

如果您的输入是“$”符号,则可以删除字符串的第一个元素,然后将其转换为double。

//method to convert String in Double
public Double getDoubleFromString(String payment) 
{
  payment = payment.substring(1);
  double paymentDouble = Double.parseDouble(payment);
  return paymentDouble;
}

String payment = keyboard.next();
double paymentDouble = getDoubleFromString(payment);

while (paymentDouble != 100.00 && paymentDouble != 50.00 && paymentDouble != 20.00 
           && paymentDouble != 10.00 && paymentDouble != 5.00 
           && paymentDouble != 2.00 && paymentDouble != 1.00) 
      {
         System.out.print("Invalid coin or note. Try again.");
         String payment = keyboard.next();
         paymentDouble = getDoubleFromString(payment);
      }

#2

public double convertPayment(String inputPayment) {   
    String payment = inputPayment.substring(1);
    double paymentValue = Double.parseDouble(payment);
    return paymentValue;
}