Question

求VB小程序代码

编写程序求s=1+2!/ 2+3!/3+...+N!/N)的值输出到一个标签中，N从一个文本框输入

Answer 1

Private Sub Command1_Click()
If Len(Text1) > 0 And IsNumeric(Text1) And Text1 <> "0" Then
Dim i, s
For i = 1 To Val(Text1)
s = s + fc(i) / i
Next
MsgBox "s=" & s
Else
With Text1
.Text = ""
.SetFocus
End With
End If
End Sub

Private Sub Form_Load()
With Label1
.Caption = ""
.AutoSize = True
End With
Text1 = 3
End Sub

Function fc(n)
Dim i
fc = 1
For i = 1 To n
fc = fc * i
Next
End Function

Answer 2

Private Sub Command1_Click()
Dim N As Long
Dim i As Long
Dim j As Long
Dim s As Long
Dim b As Long

N = Val(Text1.Text)
For i = 1 To N
b = 1
For j = 1 To i
b = b * j
Next j
s = s + b / (j - 1)

Next i
Text2.Text = s
End Sub

Answer 3

无语……
N!/N=(N-1)!