Sort in ascending order three floating point numbers

Question

import java.util.Scanner;

public class Crescente {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        double primo = in.nextDouble();
        double secondo = in.nextDouble();
        double terzo = in.nextDouble();
        if(primo > secondo && primo > terzo) {
            if(secondo > terzo) {
                System.out.println(primo+" "+secondo+" "+terzo);
            }else {
                System.out.println(primo+" "+terzo+" "+secondo);
            }
        }else if(secondo > primo && secondo > terzo) {
            if(primo > terzo) {
                System.out.println(secondo+" "+primo+" "+terzo);
            }else {
                System.out.println(secondo+" "+terzo+" "+primo);
            }
        }else if(terzo > primo && terzo > secondo) {
            if(primo > secondo) {
                System.out.println(terzo+" "+primo+" "+secondo);
            }else {
                System.out.println(terzo+" "+secondo+" "+primo);
            }
        }
        in.close();
    }
}

My program works if you enter integer numbers, but if you enter floating point numbers it gives me this error:

Exception in thread "main" java.util.InputMismatchException
    at java.base/java.util.Scanner.throwFor(Scanner.java:939)
    at java.base/java.util.Scanner.next(Scanner.java:1594)
    at java.base/java.util.Scanner.nextDouble(Scanner.java:2564)
    at poo.Crescente.main(Crescente.java:8)

I don't know why it gives me this error since I used nextDouble for all of the variables which are all double. Please help.

You typed something in the console that could not be parsed to a `double`. Please provide what you are inputting — GBlodgett, Nov 09 '18 at 19:04
@GBlodgett I've just noticed that it works if I use a comma instead of a point, like this: "4,1" instead of "4.1". Why? — user10610048, Nov 09 '18 at 19:06
I cannot reproduce that. For me it works if I use `4.2` but throws an error if I do `4,2` — GBlodgett, Nov 09 '18 at 19:08
@GBlodgett I'm from Italy, maybe it's because of that. Here we use the comma for floating point numbers. Anyway, when it prints the three numbers in ascending order, it prints them with a point. It's very strange — user10610048, Nov 09 '18 at 19:09
Hmm looks similar to this issue: https://stackoverflow.com/questions/4553633/java-float-formatting-depends-on-locale — GBlodgett, Nov 09 '18 at 19:10
That's most likely because of the LOCALE being set to `LOCALE.ITALY`, try using this `in.useLocale(Locale.ENGLISH);` before the declaration of your variables. — Nicholas K, Nov 09 '18 at 19:21

Nicholas K · Accepted Answer · 2018-11-09T19:35:35.413

Looks like your default locale is set to LOCALE.ITALY as you are from Italy. Change it to the following

Scanner in = new Scanner(System.in);
in.useLocale(Locale.ENGLISH);
// rest of the code

I was able to run the program with comma separated numbers (4,2) and decimal separated numbers (4.2) by toggling with the Locale.ITALY and Locale.ENGLISH respectively.

From the doc's :

useLocale(Locale locale)
Sets this scanner's locale to the specified locale.

Sort in ascending order three floating point numbers

1 Answers1