package strings;

/**
 * <p>
 * Alphabetical order is a system whereby character strings are placed in order
 * based on the position of the characters in the conventional ordering of an alphabet.
 * </p>
 * Wikipedia: https://en.wikipedia.org/wiki/Alphabetical_order
 */
class Alphabetical {

 public static void main(String[] args) {
 assert !isAlphabetical("123abc");
 assert isAlphabetical("aBC");
 assert isAlphabetical("abc");
 assert !isAlphabetical("xyzabc");
 assert isAlphabetical("abcxyz");
 }

 /**
 * Check if a string is alphabetical order or not
 *
 * @param s a string
 * @return {@code true} if given string is alphabetical order, otherwise {@code false}
 */
 public static boolean isAlphabetical(String s) {
 s = s.toLowerCase();
 for (int i = 0; i < s.length() - 1; ++i) {
 if (!Character.isLetter(s.charAt(i)) || !(s.charAt(i) <= s.charAt(i + 1))) {
 return false;
 }
 }
 return true;
 }
}