vb中求N1到N2自然数的和

Question

思考题：请仿照求阶乘的实验，写出求从自然数n1到自然数n2的和。（提示，要在表单中做两个输入文本框，一个用来输入起始自然数n1,另一个用来输入结束自然数n2；要在jieguo.asp中的循环求从n1到n2的累加和）

Answer 1

Private Sub Command1_Click()
Dim n1, n2, buf, mid, result As Integer

n1 = Val(Text1.Text)
n2 = Val(Text2.Text)
buf = 0
result = 0

'先判断要累加多少次
For i = n1 To n2
buf = buf + 1
Next i
MsgBox buf

mid = Int(buf / 2)

'判断个数是否偶数
If (buf Mod 2 = 0) Then result = (n1 + n2) * mid
If (buf Mod 2 = 1) Then result = (n1 + n2) * mid + (n1 + mid)

MsgBox mid
MsgBox result

End Sub