实现功能：用递归法求 1+2+3+…+100 的值，输出结果。

def s(n):

    if n==1:

        return

    else:

        return n+s( )

print("1+2+3+...+100=",s( ))

input("运行完毕，请按回车键退出...")

请完善下列程序代码：

Function prime(x As Integer) As Boolean ’此函数判断x是否为质数

  prime = True

  For i = 2 To Int(Sqr(x))

    If Then prime = False: Exit For

Next i

End Function

Private Sub Command2_Click()

Dim a As Integer, b As Integer

Dim n As Integer

For a = 2 To n \ 2

b = n - a

If Then

      List1.AddItem Str(a) + "  " + Str(b) + "  " + Str(n)

End If

          Next

End Sub

def f(n):

    if n == 5:

        return ___①___

    else:

        return _____②____

print(___③___)

    def fibs(n):

      if n==1 or n==2:

        return ____①____

      else:

        return _____②_____

    m=int(input("请输入一个整数："))

    for i in range(1,m+1):

      print(___③___ ,end=",")

  a(1)=1：a(2)=1

  b(1)=1：b(2)=2

  For i=3 To 5

a(i)=a(i-1)+a(i-2)

b(i)=b(i-1)+a(i)

Next i

执行该程序段后，数组元素b(5)的值为（  ）