Private Sub Command1_Click()
Dim a As Double, b As Integer, r As Single, n As Integer
n = 0
r = 0.01
a = 12
Do While a >= 20
a = a * (1 + r)
n = n + 1
Loop
Print n
End Sub

这是个很简单的例子，计算N，为什么我的N老为0