急求π的值求解方法格利高里算法程序的功能介绍

Dim a As Double
'pi=4*(1-1/3+1/5-1/7+1/9-1/13+1/15-1/17+...+1/(2n-1)-1/(2n+1))，

Dim s As Double
Dim n As Integer
a = -1
n = -1
Do
a = a + 2
n = -n
s = s + n / a
Loop Until a > 10 ^ 6
MsgBox s * 4

Private Sub Command1_Click()
Dim n
n = Val(InputBox("请输入π值的精度，必须大于5000！"))

Dim s As Double

For i = 1 To n

If i Mod 2 = 0 Then
s = s + (-1) * (2 * i - 1) ^ (-1)
Else
s = s + (2 * i - 1) ^ (-1)
End If
Next i
Text2.Text = s * 4
End Sub