Code Master

Recursive Programming is a technique by which a function call itself,
The source code is well commented so it's easier to understand

Place one textbox, command button and label control in your form
then copy the code below

Private Sub Button1_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles Button1.Click

Label1.Text = Factorial(Val(TextBox1.Text))

End Sub

Private Function Factorial(ByVal num As Integer)

If num = 0 Then

'If num 0 then exit the function
Factorial = 1

Else

'Otherwise call itself, with argument
'1 lower than num, the cycle will repeat
'until num<>0
Factorial = (Factorial(num - 1)) * num

End If

End Function