Question

vb编程序计算：1-1/2!+1/3!-1/4！+。。。+（-1）上标（n-1) 1/n!精度为0.000001

Answer 1

理论来说下面的代码没有错，但是我也不明白为什么不行：
Private Sub Form_Load()
Dim a As Integer, b As Integer, c As Integer, temp As Long, s As Double
Dim n As Integer
temp = 1
c = 1 'c这个变量当a是奇数时为1否则为-1,由iif()语句控制值得变化
n = Val(InputBox("请输入n的数值", "输入n值", "20"))

For a = 1 To n
For b = 1 To a
temp = temp * b
'MsgBox "b=" & b
Next
MsgBox "s=" & s
s = s + c \ temp
c = IIf(c = 1, c = -1, c = 1) '这句因该能够理解吧，如果当c=1是c就取-1,反之亦反
temp = 1
Next

MsgBox "s= " & s 'Format(s, "#.######")
End Sub
请高手一起解决该问题。