1   unit Unit1;
2   
3   interface
4   
5   uses
6     Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
7     Dialogs, StdCtrls;
8   
9   type
10    TForm1 = class(TForm)
11      Button1: TButton;
12      procedure Button1Click(Sender: TObject);
13    private
14      { Private declarations }
15    public
16      { Public declarations }
17    end;
18  
19  var
20    Form1: TForm1;
21  
22  implementation
23  
24  {$R *.dfm}
25  
26  function FileSizeByName(const Fn: string): Int64;
27  //this function returns the size of any given file in bytes
28  
29  var
30    SearchRec: TSearchRec;
31    i: Integer;
32  begin
33    try
34      i:= FindFirst(Fn, faAnyFile, SearchRec);
35      if i = 0 then Result:= SearchRec.Size
36      else Result:= -1;
37    finally
38      FindClose(SearchRec);
39    end;
40  end;
41  
42  procedure TForm1.Button1Click(Sender: TObject);
43  var
44  i:int64;
45  begin
46      i:= FileSizeByName('C:\winnt\notepad.exe');
47     showmessage('The size of the file is: '+intToStr(i)+' bytes');
48  end;
49  
50  end.