string - How to convert an integer according to international number system in java (Number Formatting) -

i want convert given number according international number system. // example:

345678 -> 345,678 12 -> 12  123 -> 123 4590 -> 4,590 

here code snippet , ideone link

public static void main (string[] args) throws java.lang.exception {     int number = 345678;     string s = integer.tostring(number);     s = putcommas(s); }  private string putcommas(string s) {     // how put commas in string after every 3rd character right ? } 

here approach not comfortable.

1. start traversing string right
2. if (length - currentindex -1) % 3 == 0 insert comma in string

any suggestions ?

you can use numberformat locale#us:

numberformat.getnumberinstance(locale.us).format(number); 

or decimalformat:

decimalformat formatter = new decimalformat("#,###"); string newnumber = formatter.format(number);