VB求1到N阶乘

Question

编写程序求S=1！+2！+3！+···+n!，n的值由键盘输入，n<13

Answer 1

Option Explicit

Private Sub Form_Load()
    Dim n As Integer, i As Integer, L As Long
    Me.AutoRedraw = True
    
    n = InputBox("输入n(n<13):")
    
    If n >= 13 Then Exit Sub
    
    
    L = 1
    For i = 1 To n Step 1
          L = L * i
    Next i
    
    Print n & "! = " & L
    
    
End Sub

Answer 2

不用任何控件，把下面的代码复制到代码窗口中，运行时单击窗口即可：

Private Sub Form_Click()
Dim S As Double, N As Integer, I As Byte
Dim St As String
Form1.AutoRedraw = True
Do
St = InputBox("N的值（N<13）", "输入", 5)
If St <> "" Then
N = Int(Val(St))
If N >= 1 And N < 13 Then Exit Do
End If
Loop
For I = 1 To N
S = S + Jc(I)
Next
Print "S("; Trim(N); ")= 1!";
For I = 2 To N
If I = 4 And N <> 4 Then
Print "+......";
ElseIf I > 4 And I <> N Then
Print "";
Else
Print "+"; I; "!";
End If
Next
Print "="; S
End Sub

Private Function Jc(X As Byte) As Double
If X = 1 Then Jc = 1 Else Jc = X * Jc(X - 1)
End Function

已经运行过。

Answer 3

Private Sub Command1_Click()
Dim aa%, bb%, cc%
bb = 1
cc = 0
aa = Val(InputBox("请输入一个小于13的整数"))
For i = 1 To aa
bb = bb * i
cc = cc + bb
Next i
MsgBox cc
End Sub

简单无控件

Answer 4

Private Sub Command1_Click()
Dim i As Integer, j As Integer, q As Long
i = Val(Text1.Text)
For j = 1 To i
q = q + ss(j)
Next j
Text2.Text = q
End Sub

Function ss(n As Integer) As Long
If n = 0 Then
ss = 1
Else
ss = n * ss(n - 1)
End If
End Function

回答完毕，期待被采纳！