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; 
        procedure Button4Click(Sender: TObject); 
        procedure Button1Click(Sender: TObject); 
        procedure Button2Click(Sender: TObject); 
        procedure Button3Click(Sender: TObject); 
        procedure Button5Click(Sender: TObject); 
        procedure Button6Click(Sender: TObject); 
        procedure Button7Click(Sender: TObject); 
        procedure Button9Click(Sender: TObject); 
        procedure Button10Click(Sender: TObject); 
        procedure Button11Click(Sender: TObject); 
        procedure Button13Click(Sender: TObject); 
        procedure Button8Click(Sender: TObject); 
        procedure Button12Click(Sender: TObject); 
        procedure Button15Click(Sender: TObject); 
        procedure Button16Click(Sender: TObject); 
        procedure Button17Click(Sender: TObject); 
        procedure Button14Click(Sender: TObject); 
    private 
        { Private declarations } 
    public 
        { Public declarations } 
    end; 
type //自定义一个Tcompute的类 

    Tcompute = object 
    private //保护类中成员数据的安全 

        temp1: double; 
        temp2: double; 
        temp3: double; 
        sign: Char; 

    public //把类中的成员函数进行共享 


        function Add(x: double; y: double): Double; 
        function Sub(x: double; y: double): Double; 
        function Mult(x: double; y: double): Double; 
        function Dived(x: double; y: double): Double; 

    end; 
var 
    Form1: TForm1; 
    Info: Tcompute; //声明Info是类Tcompute的对象 


implementation 

function Tcompute.Add(x: double; y: double): Double; //进行类的定义与实现 

begin 
    Result := x + y; 
end; 

function Tcompute.Sub(x: double; y: double): Double; 
begin 
    Result := x - y; 
end; 

function Tcompute.Mult(x: double; y: double): Double; 
begin 
    Result := x * y; 
end; 

function Tcompute.Dived(x: double; y: double): Double; 
begin 
if (y = 0) then 
    begin 
         Form1.Edit1.text:='1111111111'; 
        //ShowMessage('除数不能为0!'); //这里判断除数不能为0 

        Result := x; 
    end 
    else 
        Result := x / y; 
end; 

{$R *.dfm} 

procedure TForm1.Button4Click(Sender: TObject); 

begin 
    Edit1.Clear; 
    Info.temp1 := 0; 
    Info.temp2 := 0; 
end; 

procedure TForm1.Button1Click(Sender: TObject); 
begin 
    Edit1.Text := Edit1.text + '7'; 
    Info.temp1 := StrTofloat(Edit1.text); 
end; 

procedure TForm1.Button2Click(Sender: TObject); 

begin 
    Edit1.Text := Edit1.text + '8'; 
    Info.temp1 := StrTofloat(Edit1.text); 
end; 

procedure TForm1.Button3Click(Sender: TObject); 

begin 
    Edit1.Text := Edit1.text + '9'; 
    Info.temp1 := StrTofloat(Edit1.text); 
end; 

procedure TForm1.Button5Click(Sender: TObject); 

begin 
    Edit1.Text := Edit1.text + '4'; 
    Info.temp1 := StrTofloat(Edit1.text); 
end; 

procedure TForm1.Button6Click(Sender: TObject); 

begin 
    Edit1.Text := Edit1.text + '5'; 
    Info.temp1 := StrTofloat(Edit1.text); 
end; 

procedure TForm1.Button7Click(Sender: TObject); 

begin 
    Edit1.Text := Edit1.text + '6'; 
    Info.temp1 := StrTofloat(Edit1.text); 
end; 

procedure TForm1.Button9Click(Sender: TObject); 
begin 
    Edit1.Text := Edit1.text + '1'; 
    Info.temp1 := StrTofloat(Edit1.text); 
end; 

procedure TForm1.Button10Click(Sender: TObject); 
begin 
    Edit1.Text := Edit1.text + '2'; 
    Info.temp1 := StrTofloat(Edit1.text); 
end; 

procedure TForm1.Button11Click(Sender: TObject); 
begin 
    Edit1.Text := Edit1.text + '3'; 
    Info.temp1 := StrTofloat(Edit1.text); 
end; 

procedure TForm1.Button13Click(Sender: TObject); 
begin 
    Edit1.Text := Edit1.text + '0'; 
    Info.temp1 := StrTofloat(Edit1.text); 
end; 

procedure TForm1.Button8Click(Sender: TObject); 

begin 
    Info.temp2 := Info.temp1; 
    Info.sign := '+'; 
    Edit1.Clear; 
end; 

procedure TForm1.Button12Click(Sender: TObject); 
begin 

    Info.temp2 := Info.temp1; 
    Info.sign := '-'; 
    Edit1.Clear; 
end; 

procedure TForm1.Button15Click(Sender: TObject); 
begin 

    Info.temp2 := Info.temp1; 
    Info.sign := '*'; 
    Edit1.Clear; 
end; 

procedure TForm1.Button16Click(Sender: TObject); 
begin 
    Info.temp2 := Info.temp1; 
    Info.sign := '/'; 
    Edit1.Clear; 
end; 

procedure TForm1.Button17Click(Sender: TObject); 
begin 

    if (Info.sign = '+') then 
        Edit1.text := FloatToStr(Info.Add(Info.temp2, Info.temp1)) 
    else 
        if (Info.sign = '-') then 
            Edit1.text := FloatToStr(Info.Sub(Info.temp2, Info.temp1)) 
        else 
            if (Info.sign = '*') then 
                Edit1.text := FloatToStr(Info.Mult(Info.temp2, Info.temp1)) 
            else 
                if (Info.sign = '/') then 
                    Edit1.text := FloatToStr(Info.Dived(Info.temp2, Info.temp1)); 
    Info.temp1 := StrToFloat(Edit1.Text); 

end; 

procedure TForm1.Button14Click(Sender: TObject); 
begin 

    Edit1.Text := Edit1.Text + '.'; 
    Info.temp1 := StrToFloat(Edit1.Text); 

end; 

end.