Passing Variables through Loops

[Ed Song]

Can a subroutine both pass and call up variables? I am attempting a complex numerical iteration program that requires subroutines to both pass and call up variables. If it can't be done, is this a reason why I should switch to a Gnu Octave or Matlab program?

Because my program is very complicated, I will only show you an outline of my program (or at least what I want my program to be) which goes like this:

Option Explicit

Sub Main ()

Dim t As Integer
Dim w As Integer
Dim TotalRev As Double
Dim ErrorRev As Double
Dim ETotalRev As Double

ErrorRev = 10
t = 1
w = 1

Do
A

Do While (ErrorRev > 0.005)
B
C
D
E
F
G
H

If w = 100 Then
ErrorRev = 0.001
End If

If w > 1 And w < 100 Then
ErrorRev = Abs((ETotalRev-TotalRev)/TotalRev)
Else ErrorRev = 10
End If

w = w + 1
TotalRev = ETotalRev
Loop

(Lines of Code - Mostly printing out tables on Excel worksheet)

t = t + 1
Loop Until t = 41
End Sub

Sub A (Signature)
(Routine that sets up initial values of variables, then recalculates the values for each value of t, t = 1.....40)
End Sub

Sub B (Signature)
(Routine that takes values from A and calculates values for new variables)
End Sub

Sub C (Signature)
(Essentially the same a B but with different variables)
End Sub

Sub D (Signature)
(Essentially the same a C but with different variables)
End Sub

Sub E (Signature)
(Essentially the same a D but with different variables)
End Sub

Sub F (Signature)
(Essentially the same a E but with different variables)
End Sub

Sub G (Signature)
(Essentially the same a F but with different variables)
End Sub

Sub H (Signature)
(Aggregate Variables. Depending on the condition, the program either loops back to B or to A or program finishes)
End Sub

Subroutines B through G can be collapsed into one subroutine if I learned how to use arrays. However, it is also my understanding that arrays can only be passed through ByRef and not ByVal. I kind of know how to arrays, but I don't know how to print output on Excel worksheet using arrays.

Unfortunately, it is my understanding that a sub routine cannot both pass to or call other sub routines. It has to do one or the other, usually the main subroutine calls up variables from the other routines, and the other routines passes variable or its values to the main routine.

If this is true, then the iteration process has to be done in one subroutine. Is my analysis correct? If so, what other free programs can I learn that will produce nice tables and charts like Excel?