Base Conversion (Dec/Hex/Bin)

// Code to display the steps when converting from decimal to
   // either binary or hexadecimal (class assignment)
// Components used: frmMain, btnCalc, radToBin, radToHex, redDisplay
procedure TfrmMain.btnCalcClick(Sender: TObject);
  var iNum, d, q, r: integer;
      s, sBin: string;

begin
  redDisplay.Clear;
  if ((radToBin.Checked = False) AND (radToHex.Checked = False)) then
  begin
    ShowMessage('You need to select which conversion to perform.');
    Exit;
  end;

  iNum := StrToInt(InputBox('Input', 'Enter a number:' , ''));
  d := iNum;

  if (radToHex.Checked = True) then
  begin
    while (d > 0) do
    begin
      q := d Div 16;
      r := d Mod 16;

      s := IntToStr(d) + ' / 16 = ' + IntToStr(q) + ' rem ' + IntToStr(r);

      redDisplay.Lines.Add(s);
      d := q;
    end;

    if (d = 0) then
    begin
      redDisplay.Lines.Add('');
      s :=  'Therefore, ' + IntToStr(iNum) + ' = 0x' + IntToHex(iNum, 1);
      redDisplay.Lines.Add(s);
    end;
  end

  else if (radToBin.checked = True) then
  begin
    sBin := '';

    while (d > 0) do
    begin
      q := d Div 2;
      r := d Mod 2;

      insert(IntToStr(r), sBin, 1);  // create binary string

      s := IntToStr(d) + ' / 2 = ' + IntToStr(q) + ' rem ' + IntToStr(r);

      redDisplay.Lines.Add(s);
      d := q;
    end;

    if (d = 0) then
    begin
      redDisplay.Lines.Add('');
      s :=  'Therefore, ' + IntToStr(iNum) + ' = 0b' + sBin;
      redDisplay.Lines.Add(s);
    end;
  end;
end;