function ReplaceStr(const S, Srch, Replace: string): string;
{замена подстроки в строке}
var
  I: Integer;
  Source: string;
begin
  Source := S;
  Result := '';
  repeat
    I := Pos(Srch, Source);
    if I >
    0 then
    begin
      Result := Result + Copy(Source, 1, I - 1) + Replace;
      Source := Copy(Source, I + Length(Srch), MaxInt);
    end
    else
      Result := Result + Source;
  until I<
  = 0;
end;