There is some existing code of the follow form which is used for format numerical values:
String.format( pattern, value )
Note that I cannot change the code itself - I can only change the format pattern supplied to the code.
What is the format pattern to output a currency symbol for the default locale? Essentially, I want to achieve the following output:
String.format( "...", 123 ) => $ 123
No need to reinvent the wheel. DecimalFormat comes with currency support:
String output = DecimalFormat.getCurrencyInstance().format(123.45);
This also comes with full locale support by optionally passing in a Locale:
String output = DecimalFormat.getCurrencyInstance(Locale.GERMANY).format( 123.45);
Here's a test:
System.out.println(DecimalFormat.getCurrencyInstance().format( 123.45) );
System.out.println(DecimalFormat.getCurrencyInstance(Locale.GERMANY).format( 123.45)) ;
Output:
$123.45
123,45 €
You can try the following:
public static void main(String[] args) {
System.out.println(String.format(" %d \u20AC", 123)); // %d for integer
System.out.println(String.format(" %.2f \u20AC", 123.10)); // %f for floats
}
This prints:
123 €
123.10 €
With the constraints you have given, I think it is impossible to achieve it. To get to the current Locale's currency symbol, you'll need a minimum of code.
If you have absolutely no means to add code to the program, you'd best use the established symbol for "currency" (¤). It was established for this exact purpose, to symbolize currency absent any more specific symbol.
If you can't change the given code, but add code to the project as a whole, you can use that to find out the symbol best used. Once you have it, you can use it to create a pattern for the existing code to use for formatting.
If you can find out in which Locale the original program will run in next, you could write a assistant program that uses that setting to fill your configuration.
If there is no default Locale available, we can go with setting the currency symbol using unicode and decimal formatting. As in the below code:
For e.g. Setting the Indian currency symbol and formatting the value. This will work without user making changes in the settings.
Locale locale = new Locale("en","IN");
DecimalFormat decimalFormat = (DecimalFormat) DecimalFormat.getCurrencyInstance(locale);
DecimalFormatSymbols dfs = DecimalFormatSymbols.getInstance(locale);
dfs.setCurrencySymbol("\u20B9");
decimalFormat.setDecimalFormatSymbols(dfs);
System.out.println(decimalFormat.format(12324.13));
Output:
₹12,324.13
String formatstring=String.format("$%s", 123);
System.out.println(formatstring);
