private String gaps(int n){
  StringBuilder buf=new StringBuilder();
  for (; n > 0; n--) {
    buf.append('-');
  }
  return buf.toString();
}

private String gaps ( int n ) { StringBuilder buf = new StringBuilder ( ) ; for ( ; n > 0 ; n -- ) { buf . append ( '-' ) ; } return buf . toString ( ) ; }
get string of n gaps
