unit1.pas

很简单的计算器

unit Unit1;

interface

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

type
  TForm1 = class(TForm)
    txt1: TEdit;
    btn1: TButton;
    btn8: TButton;
    btn5: TButton;
    btn0: TButton;
    btn4: TButton;
    btn2: TButton;
    btn3: TButton;
    btn7: TButton;
    btn6: TButton;
    btndeng: TButton;
    btnnull: TButton;
    btn9: TButton;
    btndiv: TButton;
    btnmul: TButton;
    btnsub: TButton;
    btnadd: TButton;
    btndian: TButton;
    btntuige: TButton;
    procedure btn1Click(Sender: TObject);
    procedure FormCreate(Sender: TObject);
    procedure btn2Click(Sender: TObject);
   
    procedure btn3Click(Sender: TObject);
    procedure btn4Click(Sender: TObject);
    procedure btn5Click(Sender: TObject);
    procedure btn6Click(Sender: TObject);
    procedure btn7Click(Sender: TObject);
    procedure btn8Click(Sender: TObject);
    procedure btn9Click(Sender: TObject);
    procedure btn0Click(Sender: TObject);
    procedure btnaddClick(Sender: TObject);
    procedure btndengClick(Sender: TObject);
    procedure btnsubClick(Sender: TObject);
    procedure btnmulClick(Sender: TObject);
    procedure btndivClick(Sender: TObject);
    procedure btndianClick(Sender: TObject);
    procedure btnnullClick(Sender: TObject);
    procedure FormShow(Sender: TObject);


  private
    str1:string;
    str2:string;
    f : double;
    suan:integer;
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

procedure TForm1.btn1Click(Sender: TObject);
begin

str1:=str1+btn1.Caption ;
txt1.Text:=str1;
end;

procedure TForm1.FormCreate(Sender: TObject);
begin
;
end;

procedure TForm1.btn2Click(Sender: TObject);
begin
str1:=str1+btn2.Caption ;
txt1.Text:=str1;
end;


procedure TForm1.btn3Click(Sender: TObject);
begin

str1:=str1+btn3.Caption ;
txt1.Text:=str1;

end;

procedure TForm1.btn4Click(Sender: TObject);
begin
str1:=str1+btn4.Caption ;
txt1.Text:=str1;
end;


procedure TForm1.btn5Click(Sender: TObject);
begin
str1:=str1+btn5.Caption ;
txt1.Text:=str1;
end;

procedure TForm1.btn6Click(Sender: TObject);
begin
str1:=str1+btn6.Caption ;
txt1.Text:=str1;
end;

procedure TForm1.btn7Click(Sender: TObject);
begin
str1:=str1+btn7.Caption ;
txt1.Text:=str1;
end;

procedure TForm1.btn8Click(Sender: TObject);
begin
str1:=str1+btn8.Caption ;
txt1.Text:=str1;
end;

procedure TForm1.btn9Click(Sender: TObject);
begin
str1:=str1+btn9.Caption ;
txt1.Text:=str1;
end;

procedure TForm1.btn0Click(Sender: TObject);

begin
str1:=str1+btn0.Caption ;
txt1.Text:=str1;
end;

procedure TForm1.btnaddClick(Sender: TObject);
begin
str2:=str1;
str1:='';
suan:=1 ;


txt1.Text:=str1;
//f:=strtofloat(str1)+strtofloat(str2);
//str1:=floattostr(f);

end;



procedure TForm1.btndengClick(Sender: TObject);
begin
case suan of
 1: begin
    f:=strtofloat(str2)+strtofloat(str1);
    str1:=floattostr(f);
    txt1.Text:=str1;
    end;
  2: begin
    f:=strtofloat(str2)-strtofloat(str1);
    str1:=floattostr(f);
    txt1.Text:=str1;
    end;
   3: begin
    f:=strtofloat(str2)*strtofloat(str1);
    str1:=floattostr(f);
    txt1.Text:=str1;
    end;
  4: begin
    if trim(str1)='0' then
    ShowMessage('除数不能为0')

    else
    begin
    f:=strtofloat(str2)/strtofloat(str1);
    str1:=floattostr(f);
    txt1.Text:=str1;
    end;
    end;
    end;
end;

procedure TForm1.btnsubClick(Sender: TObject);
begin
str2:=str1;
str1:='';
suan:=2 ;


txt1.Text:=str1;
end;

procedure TForm1.btnmulClick(Sender: TObject);
begin
str2:=str1;
str1:='';
suan:=3 ;


txt1.Text:=str1;
end;

procedure TForm1.btndivClick(Sender: TObject);
begin
str2:=str1;
str1:='';
suan:=4 ;


txt1.Text:=str1;
end;

procedure TForm1.btndianClick(Sender: TObject);
var
 i:Integer;
begin
for i:= 1 to strlen(pChar(str1)) do
if str1[i]='.' then exit;
str1:=str1+btndian.Caption ;
txt1.Text:=str1;
end;

procedure TForm1.btnnullClick(Sender: TObject);
begin
str1:='0';
str2:='0';
txt1.Text:=str1;
end;

procedure TForm1.FormShow(Sender: TObject);
begin
txt1.Text:='0';
str1:='0';
str2:='0';
end;

end.