unit Unit1;

interface

uses
  Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
  Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls;

type
  TForm1 = class(TForm)
    Button1: TButton;
    Button2: TButton;
    Label1: TLabel;
    Label2: TLabel;
    Label3: TLabel;
    Label4: TLabel;
    Edit1: TEdit;
    Edit2: TEdit;
    Edit3: TEdit;
    Edit4: TEdit;
    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;
    procedure Button15Click(Sender: TObject);
    procedure Button1Click(Sender: TObject);
    procedure Button2Click(Sender: TObject);
    procedure Button3Click(Sender: TObject);
    procedure Button4Click(Sender: TObject);
    procedure Button5Click(Sender: TObject);
    procedure Button6Click(Sender: TObject);
    procedure Button7Click(Sender: TObject);
    procedure Button8Click(Sender: TObject);
    procedure Button9Click(Sender: TObject);
    procedure Button10Click(Sender: TObject);
    procedure Button11Click(Sender: TObject);
    procedure Button12Click(Sender: TObject);
    procedure Button13Click(Sender: TObject);
    procedure Button14Click(Sender: TObject);
    procedure Button16Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  a:Double;
  b:Double;
  c:Double;

implementation

{$R *.dfm}

procedure TForm1.Button10Click(Sender: TObject);
begin
  if Edit3.Text = '' then
    Edit1.Text:=Edit1.Text + '0'
    else
    begin
      Edit2.Text:=Edit2.Text + '0'
    end;
end;

procedure TForm1.Button11Click(Sender: TObject);
begin
  Edit3.Text:='+';
end;

procedure TForm1.Button12Click(Sender: TObject);
begin
  Edit3.Text:='-';
end;

procedure TForm1.Button13Click(Sender: TObject);
begin
  Edit3.Text:='x';
end;

procedure TForm1.Button14Click(Sender: TObject);
begin
  Edit3.Text:='/';
end;

procedure TForm1.Button15Click(Sender: TObject);
begin
Edit1.Text:='';
Edit2.Text:='';
Edit3.Text:='';
Edit4.Text:='';

end;

procedure TForm1.Button16Click(Sender: TObject);
begin
  if Edit3.Text ='+' then
    a:=StrToInt(Edit1.Text);
    b:=StrToInt(Edit2.Text);
    c:=a+b;
    Edit4.Text:=FloatToStr(c);

  if Edit3.Text ='-' then
    a:=StrToInt(Edit1.Text);
    b:=StrToInt(Edit2.Text);
    c:=a-b;
    Edit4.Text:=FloatToStr(c);

   if Edit3.Text ='*' then
    a:=StrToInt(Edit1.Text);
    b:=StrToInt(Edit2.Text);
    c:=a*b;
    Edit4.Text:=FloatToStr(c);

  if Edit3.Text ='/' then
    a:=StrToFloat(Edit1.Text);
    b:=StrToFloat(Edit2.Text);
    c:=(a)/(b);
    Edit4.Text:=FloatToStr(c)


end;

procedure TForm1.Button1Click(Sender: TObject);
begin
  if Edit3.Text = '' then
    Edit1.Text:=Edit1.Text + '1'
    else
    begin
      Edit2.Text:=Edit2.Text + '1'
    end;

end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  if Edit3.Text = '' then
    Edit1.Text:=Edit1.Text + '2'
    else
    begin
      Edit2.Text:=Edit2.Text + '2'
    end;
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  if Edit3.Text = '' then
    Edit1.Text:=Edit1.Text + '3'
    else
    begin
      Edit2.Text:=Edit2.Text + '3'
    end;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
  if Edit3.Text = '' then
    Edit1.Text:=Edit1.Text + '4'
    else
    begin
      Edit2.Text:=Edit2.Text + '4'
    end;
end;

procedure TForm1.Button5Click(Sender: TObject);
begin
  if Edit3.Text = '' then
    Edit1.Text:=Edit1.Text + '5'
    else
    begin
      Edit2.Text:=Edit2.Text + '5'
    end;
end;

procedure TForm1.Button6Click(Sender: TObject);
begin
  if Edit3.Text = '' then
    Edit1.Text:=Edit1.Text + '6'
    else
    begin
      Edit2.Text:=Edit2.Text + '6'
    end;
end;

procedure TForm1.Button7Click(Sender: TObject);
begin
  if Edit3.Text = '' then
    Edit1.Text:=Edit1.Text + '7'
    else
    begin
      Edit2.Text:=Edit2.Text + '7'
    end;
end;

procedure TForm1.Button8Click(Sender: TObject);
begin
  if Edit3.Text = '' then
    Edit1.Text:=Edit1.Text + '8'
    else
    begin
      Edit2.Text:=Edit2.Text + '8'
    end;
end;

procedure TForm1.Button9Click(Sender: TObject);
begin
  if Edit3.Text = '' then
    Edit1.Text:=Edit1.Text + '9'
    else
    begin
      Edit2.Text:=Edit2.Text + '9'
    end;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
  Form1.Text:='DELPHI CALCULATOR By: Teody';
  Form1.Position:=poMainFormCenter;
end;

end.