error in the code computing Totient Function

[sara samy]

i made application for computing totient function
but it doesn't give me any result
this is a code

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click
        Dim n As Integer
        n = CStr(TextBox1.Text)

        Dim phi As Integer
        Dim i As Integer

        phi = 0
        'Dim i As Integer
        i = 1
        Do While (i < n)
            If (gcd(i, n) = 1) Then
                phi = phi + 1
                
            Else
                Continue Do
                
            End If
        Loop

        Label3.Text = phi
    End Sub

Private Function gcd(ByVal num1 As Integer, ByVal num2 As Integer) As Integer
        Dim i As Integer
        Dim n As Integer
        
        Dim Remainder As Integer

        Do While (n <> 0)

            Remainder = i Mod n
            i = n
            n = Remainder
        Loop

        gcd = i


        Return gcd

[Joseph Martell]

At first glance I would say your problem is your variable initialization:

      Dim phi As Integer
        Dim i As Integer
 
        phi = 0
        'Dim i As Integer
        i = 1
        'Do While (1 < 0) = no execution!!!
        Do While (i < n)

Check your variable initialization and re-think your loop conditions. One of these things is wrong.