Public Function CalcSumOfDigitSequence(DigitSequence As String) As Long
'Purpose
'   Used to find the sum of a digit sequence.
'Parameters
'   DigitSequence (String) = The digit sequence we're working with.
'Return (Long)
'   Returns the sum of all digits in the sequence.
'   Function returns zero if:
'       - The sequence is zero-length, or
'       - The sequence contains only non-digits.
'   Any characters in the sequence that are not digits (0-9) are ignored.
'Version History
'   1.0 4/27/2004 Tested by Russ Tanner
'---

'Initiate variables
Dim X As String 'The current character in the loop
Dim C As Long 'Loop counter
Dim R As Long 'Return buffer

'Loop through each character in the sequence
For C = 1 To Len(DigitSequence)

    'Get the current character
    X = Mid(DigitSequence, C, 1)

    'This character is a digit (0-9), add it to the return buffer
    If InStr("0123456789", X) > 0 Then R = R + CLng(X)

Next C

'Return the result
CalcSumOfDigitSequence = R

End Function