int LastVowel (string str) {
   int i, n ;
   char c ;

   n = StringLength(str) ;
   for (i = n - 1 ; i >= 0 ; i--) {
      c = IthChar(str, i) ;
      c = tolower(c) ;
      if (c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u') {
	 return(i) ;
      }
   }

   /* No vowels found */
   return(-1) ;
}