/* Determine if a particular character is an alphanumeric character  */
int isalnum(int c)
/* Determine if a particular character is an alphanumeric character  */
int isalnum(int c)
{
  return ((('0' <= (c)) && ((c) <= '9')) ||
          (('a' <= (c)) && ((c) <= 'z')) ||
          (('A' <= (c)) && ((c) <= 'Z')));
}