Multiples.pas

program Multiples;
begin
  while (true) do begin
    var NUM, ERR, LEN, CHR: Integer;
    var MAX, IND, SUM: LongInt;
    var STR: String;
    var OKE: Boolean;
    // read max
    write('Enter MAX number: ');
    readln(STR);
    val(STR, MAX, ERR);
    if (ERR <> 0) then begin
      write('Error! ');
      continue;
    end;
    // read num
    write('Enter NUM number: ');
    readln(STR);
    val(STR, NUM, ERR);
    if (ERR <> 0) then begin
      write('Error! ');
      continue;
    end;
    // check
    if (MAX > 0) and (NUM > 1) then begin
      writeln('Working...');
      // set sum and file
      SUM := 0;
      var OUT: TextFile;
      AssignFile(OUT, MAX + '-' + NUM + '.txt');
      rewrite(OUT);
      // begin loop
      for IND := 1 to MAX do begin
        STR := IntToStr(IND);
        LEN := Length(STR);
        // length num or more
        if (LEN >= NUM) then begin
          OKE := TRUE;
          // check last num symbols
          for CHR := 1 to (NUM-1) do if (STR[LEN-CHR] <> STR[LEN]) then OKE := FALSE;
          // check one mone symbol
          if (LEN > NUM) and (STR[LEN-NUM] = STR[LEN]) then OKE := FALSE;
          // nice
          if OKE then begin
            writeln(OUT, STR);
            SUM := SUM + 1;
          end;
        end;
      end;
      // close
      CloseFile(OUT);
      write('Done! SUM = ', SUM, '. Press ENTER.');
      readln;
    end else write('Error! ');
  end;
end.