建立14个按钮，按钮的名字都要Command1，设置Index属性，0~9分别对应数字0~9，10为小数点，11为等号，12~14分别对应+、-、*和/。
2、输入如下代码：
Dim Num1, Num2 As Single
Dim StrNum1, StrNum2 As String
Dim FirstNum As Boolean
Dim PointFlag As Boolean
Dim Runsign As Integer
Dim SignFlag As Boolean
Private Sub Command1_Click(Index As Integer)
Select Case Index
Case 0 To 9
If FirstNum Then
StrNum1 = Str(Index)
FirstNum = False
Else
StrNum1 = LTrim(StrNum1) + LTrim(Str(Index))
End If
Text1.Text = Val(StrNum1)
Case 10
If Not PointFlag Then
If FirstNum Then
StrNum1 = "0."
FirstNum = False
Else
StrNum1 = LTrim(StrNum1) + LTrim(".")
End If
Else
Exit Sub
End If
PointFlag = True
Text1.Text = Val(StrNum1)
Case 12 To 15
FirstNum = True
PointFlag = False
If SignFlag Then
Call Run
Else
SignFlag = True
StrNum2 = StrNum1
StrNum1 = ""
End If
Runsign = Index - 11
Case 11
On Error Resume Next
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()
If App.PrevInstance Then MsgBox "请不要多次运行此程序，谢谢！", vbAbortRetryIgnore: Unload Me
Num1 = 0
Num2 = 0
StrNum1 = ""
StrNum2 = ""
FirstNum = True
PointFlag = False
Runsign = 0
SignFlag = False
End Sub
Sub Run()
On Error Resume Next
Dim equal As Single
Dim equal2 As Double
Num1 = Val(StrNum2)
Num2 = Val(StrNum1)
Select Case Runsign
Case 1
equal = Num1 + Num2
If Num1 >= 65536 Or Num2 >= 65536 Or equal >= 65536 Then
equal = 0
equal2 = Num1 + Num2
End If
Case 2
equal = Num1 - Num2
If Num1 >= 65536 Or Num2 >= 65536 Or equal >= 65536 Then
equal = 0
equal2 = Num1 - Num2
End If
Case 3
equal = Num1 * Num2
If Num1 >= 65536 Or Num2 >= 65536 Or equal >= 65536 Then
equal = 0
equal2 = Num1 * Num2
End If
Case 4
equal = Num1 / Num2
If Num1 >= 65536 Or Num2 >= 65536 Or equal >= 65536 Then
equal = 0
equal2 = Num1 / Num2
End If
End Select
If equal = 0 Then a = equal2 Else a = equal
StrNum2 = Str(a)
StrNum1 = StrNum2
Text1.Text = Val(StrNum2)
End Sub
Sub ClearData()
Num1 = 0
Num2 = 0
StrNum1 = ""
StrNum2 = ""
FirstNum = True
PointFlag = False
Runsign = 0
SignFlag = False
Text1.Text = 0
End Sub
