求

For语句实现

Private Sub Command1_Click()    Dim s As Long, n As Integer, i As Integer    n = Val(Text1.Text)    s = 1    For i = 1 To n        s = s * i    Next i    Label4.Caption = Str(s)End Sub

Do While语句实现

Private Sub Command1_Click()    Dim s As Long, n As Integer, i As Integer    n = Val(Text1.Text)    s = 1    i = 1    Do While i <= n        s = s * i        i = i + 1    Loop    Label4.Caption = Str(s)End Sub

学习要求：

1、读懂题意，根据每一项的变化写出通项公式。

2、设定相应的变量来解决问题，理解各变量的作用。