unit Unit1;

interface

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

type
TForm1 = class(TForm)
Edit1: TEdit;
Button1: TButton;
Button2: TButton;
Button3: TButton;
Button4: TButton;
Button5: TButton;
Button6: TButton;
Button7: TButton;
Button8: TButton;
Button9: TButton;
Button10: TButton;
Button11: TButton;
Button12: TButton;
Button13: TButton;
Button14: TButton;
Button15: TButton;
Button16: TButton;
Button17: TButton;
Button18: TButton;
Button19: TButton;
Button20: TButton;
Button21: TButton;
procedure Nabor(s: String);
procedure Deystvie;
procedure Button1Click(Sender: TObject);
procedure Button2Click(Sender: TObject);
procedure Button5Click(Sender: TObject);
procedure Button6Click(Sender: TObject);
procedure Button3Click(Sender: TObject);
procedure Button8Click(Sender: TObject);
procedure Button12Click(Sender: TObject);
procedure Button16Click(Sender: TObject);
procedure Button20Click(Sender: TObject);
procedure Button19Click(Sender: TObject);
procedure Button18Click(Sender: TObject);
procedure Button17Click(Sender: TObject);
procedure Button15Click(Sender: TObject);
procedure Button14Click(Sender: TObject);
procedure Button13Click(Sender: TObject);
procedure Button11Click(Sender: TObject);
procedure Button10Click(Sender: TObject);
procedure Button9Click(Sender: TObject);
procedure Button7Click(Sender: TObject);
procedure Button4Click(Sender: TObject);
procedure Button21Click(Sender: TObject);
private
{ Private declarations }
public
{ Public declarations }
end;

var
Form1: TForm1;
nul, drob: Boolean;
x, y: Real;
tip: Integer;

const
PLUS = 1;
MINUS = 2;
UMNOGIT = 3;
DELIT = 4;

implementation

{$R *.dfm}





procedure TForm1.Button1Click(Sender: TObject);
begin
nul := True;
drob := False;
Edit1.Text := '0';
x := 0;
y := 0;
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
Form1.Close;
end;

procedure TForm1.Button5Click(Sender: TObject);
begin
if StrToFloat(Edit1.Text) >= 0 then
Edit1.Text := FloatToStr(sqrt(StrToFloat(Edit1.Text)))
else Edit1.Text := 'Error';
nul := True;
drob := False;
end;

procedure TForm1.Button6Click(Sender: TObject);

begin
y := StrToFloat(Edit1.Text);
case tip of
PLUS: Edit1.Text := FloatToStr(x + x * y / 100);
MINUS: Edit1.Text := FloatToStr(x - x * y / 100);
UMNOGIT: Edit1.Text := FloatToStr(x * y / 100);
DELIT: begin
if y <> 0 then
Edit1.Text := FloatToStr(x / y * 100) else
Edit1.Text := 'Error';
end;
end;
nul := True;
end;


procedure TForm1.Button3Click(Sender: TObject);
begin
Nabor('7');
end;

procedure TForm1.Button8Click(Sender: TObject);
begin
Deystvie;
tip := DELIT;
end;

procedure TForm1.Button12Click(Sender: TObject);
begin
Deystvie;
tip := UMNOGIT;
end;

procedure TForm1.Button16Click(Sender: TObject);
begin
Deystvie;
tip := MINUS;
end;

procedure TForm1.Button20Click(Sender: TObject);
begin
Deystvie;
tip := PLUS;
end;

procedure TForm1.Button19Click(Sender: TObject);
begin
y := StrToFloat(Edit1.Text);
case tip of
PLUS: Edit1.Text := FloatToStr(x + y);
MINUS: Edit1.Text := FloatToStr(x - y);
UMNOGIT: Edit1.Text := FloatToStr(x * y);
DELIT: begin
if y <> 0 then
Edit1.Text := FloatToStr(x / y) else
Edit1.Text := 'Error';
end;
end;
nul := True;
end;

procedure TForm1.Button18Click(Sender: TObject);
begin
if not drob then
Nabor(',');
drob := True;

end;

procedure TForm1.Button17Click(Sender: TObject);
begin
Nabor('0');
end;

procedure TForm1.Button15Click(Sender: TObject);
begin
Nabor('3');
end;

procedure TForm1.Button14Click(Sender: TObject);
begin
Nabor('2');
end;

procedure TForm1.Button13Click(Sender: TObject);
begin
Nabor('1');
end;

procedure TForm1.Button11Click(Sender: TObject);
begin
Nabor('6');
end;

procedure TForm1.Button10Click(Sender: TObject);
begin
Nabor('5');
end;

procedure TForm1.Button9Click(Sender: TObject);
begin
Nabor('4');
end;

procedure TForm1.Button7Click(Sender: TObject);
begin
Nabor('9');
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
Nabor('8');
end;

procedure TForm1.Nabor(s: String);

begin
if (Edit1.Text = '0') or (nul) then
begin
if s = ',' then Edit1.Text := '0,' else
Edit1.Text := s;
end
else Edit1.Text := Edit1.Text + s;
nul := False;
end;

procedure TForm1.Deystvie;
begin
if Edit1.Text = 'Error' then
Edit1.Text := '0';
x := StrToFloat(Edit1.Text);
nul := True;
drob := False;
end;

procedure TForm1.Button21Click(Sender: TObject);
var s:string;
begin
s:=Form1.Edit1.Text;
if(s<>'0') then
begin
if(s[1]='-') then
begin
Delete(s,1,1);
if(s='')then s:='0';
end else
s:='-'+s;
Form1.Edit1.Text:=s;
end;
end;

end.