public class Classifier { public static void main(String[] args) { System.out.println( classify('n') + classify('+') + classify('2')); } static String classify(char ch) { if ("0123456789".indexOf(ch) >= 0) return "NUMERAL "; if ("abcdefghijklmnopqrstuvwxyz".indexOf(ch) >= 0) return "LETTER "; /* * (Operators not supported yet) * if ("+-*/&|!=".indexOf(ch) >= 0) * return "OPERATOR "; */ return "UNKNOWN "; } }