分数序列【VB代码实现】

有一个分数序列

求出这个数列的前20项之和。

代码1

Private Sub Command1_Click()
    Dim sum As Double
    Dim a As Integer, b As Integer, t As Integer
    a = 1
    b = 2
    sum = 0
    For i = 1 To 20
        sum = sum + b / a
        t = a + b
        a = b
        b = t
    Next i
    Label2.Caption = Str(sum)
End Sub

代码2

Private Sub Command1_Click()
    Dim sum As Double
    Dim a As Integer, b As Integer, t As Integer
    a = 1
    b = 2
    sum = b / a
    For i = 2 To 20
        t = a + b
        a = b
        b = t
	sum = sum + b / a
    Next i
    Label2.Caption = Str(sum)
End Sub