用vb做一个计算器

答案：
先建立一个新的项目文件，里面包含一个Form1的窗体。然后，添加控件，包括一个Text框（Text1），和17个按钮，这17个按钮使用的名称都是Command1，只是Index属性不同，就好象一个数组，创立一组按钮的方法是，先在窗体上建立一个按钮（Command1），然后在Command1上击鼠标右键，选择复制（Copy），然后在窗体上任意部位击右键，选择粘贴（Paste），系统会提示是否创建控件组，选择“是”，重复上面步骤，直至创立17个按钮为止。各控件属性如下表： 
Text1 BackColor＝&H00C0FFFF&Text＝“0.” 
Command1 Index 0――16Index 0――9 Caption=“0”－“9”Index 10 Caption=“.”Index 11 Caption=“=”Index 12 Caption=“+”Index 13 Caption=“-”Index 14 Caption=“×”Index 15 Caption=“÷”Index 16 Caption=“清除” 

代码如下： 
Dim Num1, Num2 As Single 
Dim StrNum1, StrNum2 As String 
Dim FirstNum As Boolean '判断是否是数字开头 
Dim PointFlag As Boolean '判断是否已有小数点 
Dim Runsign As Integer '储存运算符号 
Dim SignFlag As Boolean '判断是否已有运算符号 
　 
Sub ClearData() 
Num1 = 0 
Num2 = 0 
StrNum1 = " " 
StrNum2 = " " 
FirstNum = True 
PointFlag = False 
Runsign = 0 
SignFlag = False 
Text1.Text = "0. " 
End Sub 
　 
Sub Run() 
Num1 = Val(StrNum2) 
Num2 = Val(StrNum1) 
Select Case Runsign 
Case 1 
equal = Num1 + Num2 
Case 2 
equal = Num1 - Num2 
Case 3 
equal = Num1 * Num2 
Case 4 
equal = Num1 / Num2 
End Select 
StrNum2 = Str(equal) 
StrNum1 = StrNum2 
Text1.Text = StrNum2 
End Sub 
　 
Private Sub about_Click() 
MsgBox "Create by jianghuali。2007/3/7 ", vbDefaultButton1, "VB教程第四章范例 " 
End Sub 
　 
Private Sub Command1_Click(Index As Integer) 
Select Case Index 
Case 0 To 9 
If FirstNum Then 
StrNum1 = Str(Index) 
FirstNum = False 
Else 
StrNum1 = StrNum1 + Str(Index) 
End If 
Text1.Text = StrNum1 
Case 10 
If Not PointFlag Then 
If FirstNum Then 
StrNum1 = "0. " 
FirstNum = False 
Else 
StrNum1 = StrNum1 + ". " 
End If 
Else 
Exit Sub 
End If 
PointFlag = True 
Text1.Text = StrNum1 
Case 12 To 15 
FirstNum = True 
PointFlag = False 
'还原标记值 
If SignFlag Then 
Call Run 
Else 
SignFlag = True 
StrNum2 = StrNum1 
StrNum1 = " " 
End If 
Runsign = Index - 11 
Case 11 
If Not SignFlag Then 
Text1.Text = StrNum1 
equal = Val(StrNum1) 
FirstNum = True 
PointFlag = False 
Else 
Call Run 
SignFlag = False 
End If 
　 
Case Else 
Call ClearData 
　 
End Select 
End Sub 
　 
Private Sub Form_Load() 
Call ClearData 
End Sub 
用vb做这种东西是最简单的了用鼠标点简单的可以用 command控件
用键盘输入是写个KEY事件按哪个数字就直接调用哪个command控件的点击事件
连加减乘除最简单了 别把你保存数字的函数或者控件清空就可以了
sin,cos,tan,平方和立方的运算 这些VB里有内部函数直接用 后面的写下公式就可以了
Dim shu1 As Single, shu2 As Single, suanfu As String
Dim su As Boolean




Private Sub Command1_Click(Index As Integer)
  If Not su Then
    If Val(Text1.Text) = 0 And InStr(Text1.Text, ".") = 0 Then
      Text1.Text = Trim(Str(Index))
    Else
      Text1.Text = Text1.Text & Trim(Str(Index))
    End If
  Else
      shu1 = Val(Text1.Text)
      Text1.Text = Str(Index)
      su = False
  End If
    
      
  
End Sub

Private Sub Command2_Click(Index As Integer)
Call Command4_Click
suanfu = Command2(Index).Caption
su = True


End Sub

Private Sub Command3_Click()
Text1.Text = Text1.Text + "."
If (InStr(Text1.Text, ".") = 1) Then
 Text1.Text = ""
End If
If InStr(Text1.Text, ".") < Len(Text1.Text) Then
Text1.Text = Left(Text1.Text, Len(Text1.Text) - 1)
  
End If
End Sub

Private Sub Command4_Click()
shu2 = Val(Text1.Text)
  If shu1 <> 0 Then
   Select Case suanfu
     Case "+"
        Text1.Text = shu1 + shu2
     Case "-"
        Text1.Text = shu1 - shu2
     Case "*"
        Text1.Text = shu1 * shu2
     Case "/"
        If shu2 = 0 Then
         Text1.Text = ""
       Else
         Text1.Text = shu1 / shu2
       End If
     End Select
  End If
  
        
End Sub

Private Sub Command5_Click()
If Text1.Text = "" Then
Exit Sub
End If
Text1.Text = Left(Text1.Text, Len(Text1.Text) - 1)
End Sub

Private Sub Command6_Click(Index As Integer)
 Text1.Text = "0"
End Sub

Private Sub Command7_Click()
 Text1.Text = Str(Val(Text1.Text) * (-1))
End Sub

Private Sub Command8_Click()
Text1.Text = Sqr(Val(Text1.Text))
End Sub

Private Sub Command9_Click()
Text1.Text = Val(Text1.Text) / 100
End Sub

Private Sub Form_Load()
Text1.Text = ""
End Sub

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