刚学vb不久，遇到个问题难以解决，请高手指点不甚感激！！！

dim n as integer=cint(textbox1.text)
dim sum as long=0
dim i as integer=1
do while i<=n
sum+=i
i+=1
loop

dim n as integer=cint(textbox1.text)
dim sum as long=0
dim i as integer=1
do until i>n
sum+=i
i+=i
loop

加油

这段代码是错的，应该是这样：
 MsgBox(Sum(3))‘这段代码可以验证一下N为3时的结果
Private Function Sum(ByVal N As Integer) As Long
        Dim s As Long = 0
        Dim i As Integer = 1
        Do While i <= N
            Dim j As Integer = 1
            Dim s1 As Integer = 0
            Do While j <= i
                s1 += j
                j += 1
            Loop
            s += s1
            i += 1
        Loop
        Return s
    End Function