PROCEDURE Lowerize(VAR Str : String);
  VAR L,V : Integer;
BEGIN
  FOR L := 1 TO MaxString DO
    BEGIN
      V := Ord(Str[L]);
      IF (91 > V) AND (V > 64) THEN
        Str[L] := Chr(V + 32)
    END
END;(* letters to lower case *)

PROCEDURE Upperize(VAR Str : String);
  VAR L,V : Integer;
BEGIN
  FOR L := 1 TO MaxString DO
    BEGIN
      V := Ord(Str[L]);
      IF (123 > V) AND (V > 96) THEN
        Str[L] := Chr(V - 32)
    END
END;(* letters to upper case *)

PROCEDURE Invertize(VAR Str : String);
  VAR
     L,V : Integer;
BEGIN
 FOR L := 1 TO MaxString DO
  BEGIN
   V := Ord(Str[L]);
   Str[L] := Chr(V + 128)
  END
END;(* all of string to inverse *)

PROCEDURE Purge(VAR Str : String);
  VAR L,V : Integer;
BEGIN
  FOR L := 1 TO MaxString DO
    BEGIN
      V := Ord(Str[L]);
      IF (V < 32) OR (V > 122) THEN Str[L] := Chr(32)
    END
END;