unit2.pas

Delphi 有很多很好的例子

unit Unit2;

interface

uses
  Windows, Messages, SysUtils, 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;
    Button16: TButton;
    Label1: TLabel;
    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 Button15Click(Sender: TObject);
    procedure Button16Click(Sender: TObject);
  private
    { Private declarations }
  public
    { Public declarations }
  end;

var
  Form1: TForm1;
  temp1: string;
  temp2: real;
  n:  integer;

implementation

{$R *.DFM}

procedure TForm1.Button1Click(Sender: TObject);
begin
  edit1.Text:=edit1.Text+'1'  //在运算框中输入数字"1"
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
  edit1.Text:=edit1.Text+'2'    //在运算框中输入数字2
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
  edit1.Text:=edit1.Text+'3'    //在运算框中输入数字3
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
  edit1.Text:=edit1.Text+'4'    //在运算框中输入数字4
end;

procedure TForm1.Button5Click(Sender: TObject);
begin
  edit1.Text:=edit1.Text+'5'    //在运算框中输入数字5
end;

procedure TForm1.Button6Click(Sender: TObject);
begin
  edit1.Text:=edit1.Text+'6'    //在运算框中输入数字6
end;

procedure TForm1.Button7Click(Sender: TObject);
begin
  edit1.Text:=edit1.Text+'7'    //在运算框中输入数字"7"
end;

procedure TForm1.Button8Click(Sender: TObject);
begin
  edit1.Text:=edit1.Text+'8'    //在运算框中输入数字"8"
end;

procedure TForm1.Button9Click(Sender: TObject);
begin
  edit1.Text:=edit1.Text+'9'    //在运算框中输入数字"9"
end;

procedure TForm1.Button10Click(Sender: TObject);
begin
  edit1.Text:=edit1.Text+'0'    //在运算框中输入数字"0"
end;

procedure TForm1.Button12Click(Sender: TObject);
begin
  edit1.Clear    //清除文本框
end;

procedure TForm1.Button13Click(Sender: TObject);
begin
  n:=1;                 //设置加法标志变量
  temp1:=edit1.text;    //为临时变量temp1赋值
  edit1.clear;          //清空运算框
end;

procedure TForm1.Button14Click(Sender: TObject);
begin
  n:=2;
  temp1:=edit1.text;
  edit1.clear;
end;

procedure TForm1.Button15Click(Sender: TObject);
begin
  n:=3;
  temp1:=edit1.text;
  edit1.clear;
end;

procedure TForm1.Button16Click(Sender: TObject);
begin
  n:=4;
  temp1:=edit1.text;
  edit1.clear;      
end;

procedure TForm1.Button11Click(Sender: TObject);
begin
  case n of
       1:temp2:=strtofloat(temp1)+strtofloat(edit1.text);
       2:temp2:=strtofloat(temp1)-strtofloat(edit1.text);
       3:temp2:=strtofloat(edit1.text)*strtofloat(temp1);
       4:if strtofloat(edit1.text)=0 then
          begin
             showmessage('除数为0！');
             exit;
          end
         else
       temp2:=strtofloat(temp1)/strtofloat(edit1.text);
   end;
   edit1.text:=floattostr(temp2);
end;
end.