unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    Cislo: TButton;
    Button1: TButton;
    Button2: TButton;
    Button3: TButton;
    Button4: TButton;
    Button5: TButton;
    Button6: TButton;
    Button7: TButton;
    Button8: TButton;
    Button9: TButton;
    Button10: TButton;
    Dis: TLabel;
    Opera: TButton;
    Button11: TButton;
    Button12: TButton;
    Button13: TButton;
    Button14: TButton;
    OST: TButton;
    Button15: TButton;
    Button16: TButton;
    Button17: TButton;
    Button18: TButton;
    Button19: TButton;
    procedure FormCreate(Sender: TObject);
    procedure CisloClick(Sender: TObject);
    procedure OperaClick(Sender: TObject);
    procedure OSTClick(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  COper:integer;
  Smaz:boolean;
  Minuly:string;
implementation

{$R *.DFM}

procedure TForm1.FormCreate(Sender: TObject);
begin
   Dis.caption:='';Minuly:='';
   COper:=-1;Smaz:=False;
end;

procedure TForm1.CisloClick(Sender: TObject);
begin
   if Smaz then dis.caption:='';
   Smaz:=false;
   dis.caption:=dis.caption+(sender as tbutton).caption;
end;

procedure TForm1.OperaClick(Sender: TObject);
Var s:string;
    a,b,c:double;
begin
  s:=(sender as tbutton).caption;
  smaz:=true;
  If COper<>-1 then begin
     a:=strtofloat(minuly);
     b:=strtofloat(dis.caption);
     if Coper=1 then c:=a+b else
     if Coper=2 then c:=a-b else
     if Coper=3 then c:=a*b else
     if Coper=4 then c:=a/b;
     Dis.Caption:=floattostr(c);
  End;
  if s='+' then COper:=1 else if s='-' then COper:=2
     else if s='*' then COper:=3 else if s='/' then COper:=4
     else COper:=-1;
  Minuly:=Dis.caption;
end;

procedure TForm1.OSTClick(Sender: TObject);
var s:string;
begin
   s:=(sender as tbutton).caption;
   If s='Ce' then dis.caption:=''
   else if s='AC' then begin Dis.caption:='';COper:=-1;End
   else if s='v--' then Begin dis.caption:=floattostr(sqrt(strtofloat(dis.caption)));Smaz:=True;End
   else if s='Sin' then Begin dis.caption:=floattostr(sin(strtofloat(dis.caption)));Smaz:=True;End
   else if s='Cos' then Begin dis.caption:=floattostr(cos(strtofloat(dis.caption)));Smaz:=True;End
   else if s='Tan' then Begin dis.caption:=floattostr(sin(strtofloat(dis.caption))/cos(strtofloat(dis.caption)));Smaz:=True;End;
end;

end.