求n的阶乘【VB代码实现】

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。