Поиск указанных букв в тексте

unit MainU;
 
interface
 
uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, Buttons, StdCtrls;
 
type
  TForm1 = class(TForm)
    memText: TMemo;
    Label1: TLabel;
    ledFind: TEdit;
    btnFind: TButton;
    lblMessage: TLabel;
    btnClear: TButton;
    BitBtn1: TBitBtn;
    procedure btnFindClick(Sender: TObject);
    procedure btnClearClick(Sender: TObject);
    procedure BitBtn1Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;
 
var
  Form1: TForm1;
 
implementation
 
{$R *.dfm}
 
procedure TForm1.btnFindClick(Sender: TObject);
var
i,k:integer;
l:char;
s:string;
begin
if length(ledFind.Text)<1 then
begin
lblMessage.Visible:=true;
lblMessage.Caption:='Буква не введена!';
exit;
end;
l:=ledFind.Text[1];
s:=memtext.Text;
k:=0;
for i:=1 to length(s) do
if s[i]=l then
k:=k+1;
lblMessage.Visible:=true;
lblMessage.Caption:='Количество букв: '+inttostr(k);
end;
 
procedure TForm1.btnClearClick(Sender: TObject);
begin
ledFind.Text:='';
ledFind.SetFocus;
lblMessage.Caption:='';
lblMessage.Visible:=false;
end;
 
procedure TForm1.BitBtn1Click(Sender: TObject);
begin
close;
end;
 
end.