Delphi 实现简单计算器

unit Cals;

interface

uses

Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,

Dialogs, Menus, StdCtrls;

type

TForm1 = class(TForm)

mm1: TMainMenu;

N1: TMenuItem;

S1: TMenuItem;

S2: TMenuItem;

edt1: TEdit;

Button1: TButton;

Button2: TButton;

Button3: TButton;

Button4: TButton;

Button5: TButton;

Button6: TButton;

Button7: TButton;

Button8: TButton;

Button9: TButton;

Button11: TButton;

Button12: TButton;

Button13: TButton;

Button14: TButton;

Button15: TButton;

Button16: TButton;

Button18: TButton;

Button19: TButton;

Button20: TButton;

Button21: TButton;

Button22: TButton;

Button23: TButton;

Button25: TButton;

Button26: TButton;

Button27: TButton;

Button28: TButton;

Button29: TButton;

Button30: TButton;

edt2: TEdit;

procedure Button19Click(Sender: TObject);

procedure Button26Click(Sender: TObject);

procedure Button1Click(Sender: TObject);

procedure Button2Click(Sender: TObject);

procedure Button3Click(Sender: TObject);

procedure Button20Click(Sender: TObject);

procedure Button21Click(Sender: TObject);

procedure Button12Click(Sender: TObject);

procedure Button13Click(Sender: TObject);

procedure Button14Click(Sender: TObject);

procedure Button5Click(Sender: TObject);

procedure Button6Click(Sender: TObject);

procedure Button7Click(Sender: TObject);

procedure Button29Click(Sender: TObject);

procedure Button30Click(Sender: TObject);

procedure Button22Click(Sender: TObject);

procedure Button15Click(Sender: TObject);

procedure Button8Click(Sender: TObject);

procedure Button27Click(Sender: TObject);

procedure Button28Click(Sender: TObject);

procedure Button9Click(Sender: TObject);

procedure Button23Click(Sender: TObject);

procedure UpdateDisplay();

procedure Calculate();

procedure OnOperandInput(a: Integer);

procedure edt1KeyPress(Sender: TObject; var Key: Char);

procedure FormCreate(Sender: TObject);

procedure Button16Click(Sender: TObject);

procedure Button4Click(Sender: TObject);

procedure Button11Click(Sender: TObject);

procedure Button18Click(Sender: TObject);

procedure Button25Click(Sender: TObject);

private

{ Private declarations }

public

{ Public declarations }

end;

type

Operator = (OpNone,OpAdd,OpSubtract,OpMultiply,OpDivide);//定义枚举用以标识运算符

CalcError = (ErrNone,ErrDivideByZero); //定义枚举用以标识当前运算状态

var

Form1: TForm1;

m_operator : Operator = OpNone; //定义枚举变量 m_operator 用以标识当前运算符

m_newsign : Boolean = False; //标记是否输入新的操作数：1是，0否

m_realsign : Boolean = False; //标记是否输入小数： 1是，0否 m_operand : Real = 0; //存储当前输入的数

m_errorState : CalcError = ErrNone; // 定义枚举变量m_errorState 用以标识当前运算状态

m_accum : Real; //存储当前的计算处理结束—>操作数

m_coff : Real = 0.1; //小数输入时的系数

m_memory : Real = 0; // 使用内存中存储的数字implementation

{$R *.dfm}

uses StrUtils;

procedure TForm1.FormCreate(Sender: TObject);

begin

edt1.Text := '0';

end;

procedure TForm1.edt1KeyPress(Sender: TObject; var Key: Char);

begin

if not (key in ['0', '1', '2', '3', '4', '5', '6', '7', '8', '9', #8]) then

key := char(0);

end;

//Backspace

procedure TForm1.Button1Click(Sender: TObject);

begin

if m_operand = 0 then edt1.Text := '0'

else

edt1.Text := Copy(edt1.Text,1,Length(edt1.Text) - 1);

if edt1.Text = '' then edt1.Text := '0';

m_operand := StrToFloat(edt1.Text);

UpdateDisplay();

end;

//CE

procedure TForm1.Button2Click(Sender: TObject);

begin

m_operand := 0;

UpdateDisplay();

end;

//C

procedure TForm1.Button3Click(Sender: TObject);

begin

m_operator := OpNone;

m_operand := 0;

m_accum := 0;

m_realsign := False;

m_errorState := ErrNone;

m_coff := 0.1;

m_newsign := False;

UpdateDisplay();

end;

//处理数字输入

procedure TForm1.OnOperandInput(a: Integer);

begin

//判断是否输入新的数字，1-是 0-否

if not m_newsign then m_operand := 0;

//判断是否是小数输入，1-是 0-否

if not m_realsign then m_operand := m_operand * 10 + (a) else

begin

m_operand := m_operand + a * m_coff;

m_coff := m_coff * 0.1;

end;

m_newsign := True;

UpdateDisplay();

end;

//计算处理函数 OpAdd,OpSubtract,OpMultiply,OpDivide procedure TForm1.Calculate();

begin

if m_newsign = True then

begin

//如果没有计算符就直接将m_operand值赋予m_accum

if m_operator = OpNone then

m_accum := m_operand

//否则先按计算符进行计算操作再值赋予m_accum

else if m_operator = OpAdd then

m_accum := m_accum + m_operand

else if m_operator = OpSubtract then

m_accum := m_accum - m_operand

else if m_operator = OpMultiply then

m_accum := m_accum * m_operand

else if m_operator = OpDivide then

begin

if m_operand = 0 then m_errorState := ErrDivideByZero else

m_accum := m_accum / m_operand;

end

end;

m_newsign := False;

m_realsign := False;

m_coff := 0.1;

UpdateDisplay();

end;

//处理显示

procedure TForm1.UpdateDisplay();

var m_temp : Real;

begin

if m_errorState <> ErrNone then

edt1.Text := '除数不能为零'

else

begin

if m_newsign then m_temp := m_operand

else m_temp := m_accum;

//edt1.Text := Format('%d',[m_temp]);

edt1.Text := FloatToStr(m_temp);

end;

end;

//数字0~9

procedure TForm1.Button26Click(Sender: TObject);

begin

OnOperandInput(0);

end;

procedure TForm1.Button19Click(Sender: TObject);

begin

OnOperandInput(1);

end;

procedure TForm1.Button20Click(Sender: TObject); begin

OnOperandInput(2);

end;

procedure TForm1.Button21Click(Sender: TObject); begin

OnOperandInput(3);

end;

procedure TForm1.Button12Click(Sender: TObject); begin

OnOperandInput(4);

end;

procedure TForm1.Button13Click(Sender: TObject); begin

OnOperandInput(5);

end;

procedure TForm1.Button14Click(Sender: TObject); begin

OnOperandInput(6);

end;

procedure TForm1.Button5Click(Sender: TObject); begin

OnOperandInput(7);

end;

procedure TForm1.Button6Click(Sender: TObject); begin

OnOperandInput(8);

end;

procedure TForm1.Button7Click(Sender: TObject); begin

OnOperandInput(9);

end;

// +

procedure TForm1.Button29Click(Sender: TObject); begin

Calculate();

m_operator := OpAdd;

end;

// -

procedure TForm1.Button22Click(Sender: TObject); begin

Calculate();

m_operator := OpSubtract;

end;

// *

procedure TForm1.Button15Click(Sender: TObject); begin

Calculate();

m_operator := OpMultiply;

end;

// /

procedure TForm1.Button8Click(Sender: TObject); begin

Calculate();

m_operator := OpDivide;

end;

// =

procedure TForm1.Button30Click(Sender: TObject); begin

Calculate();

m_operator := OpNone;

end;

// +/-

procedure TForm1.Button27Click(Sender: TObject); begin

m_operand := m_operand * (-1);

UpdateDisplay();

end;

// .

procedure TForm1.Button28Click(Sender: TObject); begin

m_realsign := True;

UpdateDisplay();

end;

//开平方

procedure TForm1.Button9Click(Sender: TObject);

begin

m_operand := Sqrt(m_operand);

UpdateDisplay();

end;

//求倒

procedure TForm1.Button23Click(Sender: TObject);

begin

if m_operand = 0 then m_errorState := ErrDivideByZero else

m_operand := 1 / m_operand;

UpdateDisplay();

end;

// %

procedure TForm1.Button16Click(Sender: TObject);

var i : Integer;

begin

//??????

m_operand := m_operand / 100;

UpdateDisplay();

end;

// 计算器有关内存操作

// 'MC'的操作，将内存清0

procedure TForm1.Button4Click(Sender: TObject);

begin

m_memory := 0;

edt2.Text := '';

//ShowMessage(FloatToStr(m_memory));

end;

// 'MR'的操作，将存储器中的信息输出

procedure TForm1.Button11Click(Sender: TObject);

begin

m_newsign := True; //很关键

m_operand := m_memory;

UpdateDisplay();

//ShowMessage(FloatToStr(m_memory));

end;

// 'MS'的操作，将当前文本框内容保存入内存，显示'M'

procedure TForm1.Button18Click(Sender: TObject);

begin

if m_operand <> 0 then

begin

edt2.Text := ' M';

m_memory := m_operand;

//ShowMessage(FloatToStr(m_memory));

end;

end;

// 'M+'的功能，将当前文本框里的数据和存储器中数据相加后，再存入存储器procedure TForm1.Button25Click(Sender: TObject);

begin

m_memory := m_memory + m_operand;

//ShowMessage(FloatToStr(m_memory));

end;

end.