Question

I am new to VBA and trying to write a simple macro. I have pasted my code below. Basically, I have 11 random numbers in cells B5 through B15. If this number is less than 0.65 I would like it to print TRUE in the column next to it. If it is greater than 0.65 I would like it to print FALSE in the column next to it. I think I basically have the code down, however a “Next t” in the Sub PrintandRead, t will have a value 5 through 15 (which is correct) however then it goes up to the markov function where t then returns to t=0. Why is it not carrying the “Next t” value up into the function?

Option Explicit

Function markov(pwd As Double, pww As Double) As Boolean
    Static wetYesterday As Boolean
    pwd = 0.4
    pww = 0.65
    Dim c As Double
    Dim t As Double
    If wetYesterday Then c = t - pww Else c = t - pwd
    If c <= 0 Then
        wetYesterday = True: markov = True
    Else
    wetYesterday = False: markov = False
    End If
End Function


Sub ReadAndPrint()
    Dim t As Double
    Dim p As Double
    Dim z(11) As Double
    Application.ScreenUpdating = False
    Worksheets("Sheet1").Activate
    p = 2
    For t = 5 To 15
        z(t - 4) = Cells(t, p)
    Next t
    p = p + 1
    For t = 5 To 15
    Cells(t, p) = markov(0.4, 0.65)
    'z(t - 4)
    Next t

End Sub

Answer 1

While you have a variable called t in your markov function, this is a different variable to the one in the main ReadAndPrint method. This is called scope – as you declare each variable within each method, it is scoped to that method. You can use the same name again elsewhere, but its a completely different variable (and could have a different type etc).

The best thing you could do would be to pass t into the markov method as a parameter by changing the declaration:

Function markov(pwd As Double, pww As Double,t as Double) As Boolean

and calling it with

Cells(t, p) = markov(0.4, 0.65, z(t - 4))

You should also delete the Dim t As Double from the markov function.