Private Sub Command1_Click()

Dim a As Integer, b As Integer

a = 5: b = 3

Print work(a, b)

End Sub

Function work(x As Integer, y As Integer) As Integer

If (x < y) Then

work = 0

Exit Function

End If

If (y = 0) Then

work = 1

Exit Function

End If

work = work(x - 1, y - 1) + work(x - 1, y)

End Function

实现上述功能的程序如下，请在划线处填入合适的代码。

def isprime(x):

    for i in range(2,x):

        if {#blank#}1{#/blank#} :

            return False

    return True

n=int(input("请输入一个正整数 n:"))

c=0

k=3

while k<=n-2:

    if isprime(k) and {#blank#}2{#/blank#} :

        print(k,k+2)

        {#blank#}3{#/blank#}

    k=k+1

print("共有"+str(c)+"对双胞胎数")

实现上述功能的VB代码如下。

Dim a(1 To 50) As Integer

Private sub Command1_Click()

    Dim i As Integer

    k=0: i=3

    Do While i<= 100

        If Not prime(i) Then

            k=k+1

        End If

        i=i+2

    Loop

    For i=2 To k

        If         Then

            List1 AddItem Str(a(i-1))+"和"+ Str(a(i))

        End if

    Next i

End Sub

Function prime (x As Integer)As Boolean

    prime=False

    For i=2 To Int(sar(x))

        If x Mod i=0 Then

            prime=True

            Exit for

        End If

    Next i

End Function

def f(x):

    if x<=1 :

        return 2

    else:

        return f(x-1)*2+f(x-2)

执行语句 v=f(3)，v 的值为（   ）