使用visual basic的递归/ Fibonacci

Question

Public Class Form1

Private Function fib()
    Dim result As Integer

    If (NUD1.Value < 2) Then
        result = 1
        Return result
    Else
        result = fib(NUD1.Value - 1) + fib(NUD1.Value - 2)
        Return result

    End If

End Function


Private Sub btnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStart.Click

    LbFb1.Items.Add(fib())
End Sub

End Class

For some reason it only returns value a value for 0,1 and crashes if I go above 2. Any ideas ?

Answer 1

you are not modifying NUD1.value upon each recursion the value has to be updated that is the logic of this function

    Function fib(ByVal n)
    If n < 2 Then Return n Else Return fib(n - 1) + fib(n - 2)
    End Function

In this case if your returning "Result" it should be passed in the next recurring function but in this case you are passing NUD1.value which is incorrect