http://www.awitness.org/delphi_pascal_tutorial/index.html

If you ever need to convert a hexadecimal number in the form of a string into an integer value, this function will perform the task.  Some possible improvements.  Do an uppercase on the string and save a few lines of code in the case statement.  There might also be an exponential function built into Delphi (I didn't look).  No error checking is included here (checking for valid Hex numbers and letters in the input string).



unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Edit1: TEdit; {integer to string}
    Button1: TButton;
    Edit2: TEdit; {hex string}
    StaticText1: TStaticText; {Hex string}
    StaticText2: TStaticText;  {integer}
    procedure Button1Click(Sender: TObject);
    function HexStringToInt(hexnum:string):integer;
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
begin
Edit1.Text:=IntToStr(HexStringToInt(Edit2.Text));
end;
function TForm1.HexStringToInt(hexnum:string):integer;
var
 s:char; s_ord:integer; i, j:integer;  hnum:integer; sixteen: integer;
begin
     result:=0; hnum:=0;
     for i:=length(hexnum) downto 1 do begin
         s:=hexnum[i]; s_ord:=ord(s);
         case s_ord of
              ord('0') : hnum:=0;
              ord('1') : hnum:=1;
              ord('2') : hnum:=2;
              ord('3') : hnum:=3;
              ord('4') : hnum:=4;
              ord('5') : hnum:=5;
              ord('6') : hnum:=6;
              ord('7') : hnum:=7;
              ord('8') : hnum:=8;
              ord('9') : hnum:=9;
              ord('A') : hnum:=10;
              ord('a') : hnum:=10;
              ord('B') : hnum:=11;
              ord('b') : hnum:=11;
              ord('C') : hnum:=12;
              ord('c') : hnum:=12;
              ord('D') : hnum:=13;
              ord('d') : hnum:=13;
              ord('E') : hnum:=14;
              ord('e') : hnum:=14;
              ord('F') : hnum:=15;
              ord('f') : hnum:=15;
         end; {case}
         if i=length(hexnum) then result:=hnum  {simulate exponential function}
         else begin
             sixteen:=1;
             for j:=length(hexnum)-i downto 1 do
             sixteen := sixteen * 16;
             result:=result + (hnum * sixteen);
         end;

      end;  {for loop}
end; {hext to int function}

procedure TForm1.FormCreate(Sender: TObject);
begin
Form1.Height:=198;
Form1.Width:=236;
end;

end.