为什么我只能输入“ 1,5”而不输入“ 1.5”

Question

I coded a little program to calculate a tax, but I have a problem. The problem multiplies the number that I put in by 0.9975, but I can only put in a double number with a "," and not with a dot ".".

import java.util.Scanner;

public class Bitrex {
    public static void main(String[] args) {
        Scanner Bitcoin = new Scanner (System.in);
        double num1;
        double num2=0.9975;
        double answer;

        System.out.println("Enter Expected Price: ");
        num1 = Bitcoin.nextDouble();
        answer = num1 * num2;
        System.out.println(answer);
    } // end of main
}

Answer 1

You probably are in Germany and Scanner uses the default Locale , that is, , is used as the decimal separator for parsing. See the Javadoc of Scanner .

You should set the Locale you want to use like in

...

Scanner Bitcoin = new Scanner (System.in);
Bitcoin.useLocale(Locale.US);  // or Locale.ROOT  or  new Locale("pt", "BR")

...

(do not forget import java.util.Locale; )

Eventually it is better to set the default Locale for the whole application using Locale.setDefault(Locale.ROOT);