// SumDouble.java public class SumDouble { public static void main(String[] args) { double sum = 0; for (String argument : args) { StringBuilder number = new StringBuilder(); for (char c : argument.toCharArray()) { if (!Character.isWhitespace(c)) { number.append(c); } else { sum += parseNumber(number); // method call number = new StringBuilder(); } } sum += parseNumber(number); // method call } System.out.println(sum); } static double parseNumber(StringBuilder number) { return number.isEmpty() ? 0.0 : Double.parseDouble(number.toString()); } }