Шифрование

const
  n = 3;
 
function CaesarEncipher(toCode: string): string;
var i, T: integer;
begin
  for i := 1 to length(toCode) do begin
    T := (Ord(toCode[ i ]) + n);
    if T >= 256 then dec(T, 256);
    toCode[ i ] := Chr(T);
  end;
  CaesarEncipher := toCode;
end;
 
function CaesarDecipher(toDecode: string): string;
var i, T: integer;
begin
  for i := 1 to length(toDecode) do begin
    T := (Ord(toDecode[ i ]) - n);
    if T < 0 then Inc(T, 256);
    toDecode[ i ] := Chr(T);
  end;
  CaesarDecipher := toDecode;
end;
 
{ применение: }
var
  s: string;
 
begin
  s := CaesarEncipher('just a Caesar');
  writeln(s);
  writeln('s = ', CaesarDecipher(s));
end.