Question

用delphi做一个简单计算器

代码在下面
可是它总是在temp:=edit1.Text;这边报错，为什么呢？

procedure TForm1.Button1Click(Sender: TObject);
begin
edit1.Text:=edit1.Text+'1';
end;

procedure TForm1.Button2Click(Sender: TObject);
begin
edit1.Text:=edit1.text+'2';
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
temp:=edit1.Text;
edit1.clear;
flag:=0;
end;

procedure TForm1.Button4Click(Sender: TObject);
begin
temp:=edit1.text;
edit1.clear;
flag:=1;
end;

procedure TForm1.Button5Click(Sender: TObject);
begin
temp:=edit1.text;
edit1.clear;
flag:=2;
end;

procedure TForm1.Button6Click(Sender: TObject);
begin
temp:=edit1.text;
edit1.clear;
flag:=3;
end;

procedure TForm1.Button7Click(Sender: TObject);
begin
case flag of
0: edit1.Text:=inttostr(strtoint(temp)+strtoint(edit1.text));
1: edit1.Text:=inttostr(strtoint(temp)-strtoint(edit1.text));
2: edit1.Text:=inttostr(strtoint(temp)*strtoint(edit1.text));
3: edit1.Text:=inttostr(trunc(strtoint(temp)/strtoint(edit1.text)));
end;

end.

Answer 1

试试这个

unit Unit1;

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;
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);
procedure FormCreate(Sender: TObject);
private
procedure SetEditText(info: string);
{ 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
oldinfo:string;

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
oldinfo := '';
SetEditText('');
Info.sign := ' ';
Info.temp1 := 0;
Info.temp2 := 0;
end;

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

procedure TForm1.Button2Click(Sender: TObject);
begin
SetEditText('8');
Info.temp1 := StrTofloat(Edit1.text);
end;

procedure TForm1.Button3Click(Sender: TObject);
begin
SetEditText('9');
Info.temp1 := StrTofloat(Edit1.text);
end;

procedure TForm1.Button5Click(Sender: TObject);
begin
SetEditText('4');
Info.temp1 := StrTofloat(Edit1.text);
end;

procedure TForm1.Button6Click(Sender: TObject);
begin
SetEditText('5');
Info.temp1 := StrTofloat(Edit1.text);
end;

procedure TForm1.Button7Click(Sender: TObject);
begin
SetEditText('6');
Info.temp1 := StrTofloat(Edit1.text);
end;

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

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

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

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

procedure TForm1.Button8Click(Sender: TObject);
begin
Button17Click(nil);
Info.temp2 := Info.temp1;
Info.sign := '+';
oldinfo := '';
end;

procedure TForm1.Button12Click(Sender: TObject);
begin
Button17Click(nil);
Info.temp2 := Info.temp1;
Info.sign := '-';
oldinfo := '';
end;

procedure TForm1.Button15Click(Sender: TObject);
begin
Button17Click(nil);
Info.temp2 := Info.temp1;
Info.sign := '*';
oldinfo := '';
end;

procedure TForm1.Button16Click(Sender: TObject);
begin
Button17Click(nil);
Info.temp2 := Info.temp1;
Info.sign := '/';
oldinfo := '';
end;

procedure TForm1.Button17Click(Sender: TObject);
begin
if Info.sign<>' ' then oldinfo := '';
if (Info.sign = '+') then
SetEditText(FloatToStr(Info.Add(Info.temp2, Info.temp1)))
else if (Info.sign = '-') then
SetEditText(FloatToStr(Info.Sub(Info.temp2, Info.temp1)))
else if (Info.sign = '*') then
SetEditText(FloatToStr(Info.Mult(Info.temp2, Info.temp1)))
else if (Info.sign = '/') then
SetEditText(FloatToStr(Info.Dived(Info.temp2, Info.temp1)));
if Edit1.Text<>'' then
Info.temp1 := StrToFloat(Edit1.Text);
Info.sign := ' ';
end;

procedure TForm1.Button14Click(Sender: TObject);
begin
SetEditText('.');
Info.temp1 := StrToFloat(Edit1.Text);
end;

procedure TForm1.SetEditText(info:string);
begin
Edit1.Text := oldinfo + info;
oldinfo := Edit1.Text;
end;

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

end.

追问

看不懂哎，老师给我们的程序就是我发的，可我不明白为什么他会报错。。。