Here is my attempt to solve the About.com Delphi challenge to un-camel-case a string.

unit challenge1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, StdCtrls;

type
   check = 65..90;
  TForm1 = class(TForm)
    Edit1: TEdit;
    Button1: TButton;
    procedure Button1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  var s1,s2 :string;
  int : integer;

implementation

{$R *.dfm}

procedure TForm1.Button1Click(Sender: TObject);
var
  i: Integer;
  checks : set of check;
begin
  s1 := edit1.Text;
  for i := 1 to 20  do
  begin
    int  :=ord(s1[i]) ;
    if int in checks then
      insert('  ',s1,i-1);
  end;
  showmessage(s1); 
end;

end.

check is a set that contains capital letters so basically whenever a capital letter is encountered the insert function adds space before its encountered (inside the s1 string), but my code does nothing. ShowMessage just shows text as it was entered in Edit1. What have I done wrong?