Problem with loop

[Kim]

Hi, why doesn't this work inside a loop, gives me the wrong "kontrollnummer"
(increases it as the loop goes on)

<%
Dim kontrollnummer
Dim raknare
Dim Summa
Dim referens
referens = (rs_faktura.Fields.Item("customer_ID").Value) &
(rs_faktura.Fields.Item("bill_ID").Value)

Dim faktor
faktor = 7

For raknare = Len(referens) To 1 Step -1
Summa = Summa + Mid(referens, raknare, 1) * faktor
If faktor = 7 Then
faktor = 3
ElseIf faktor = 3 Then
faktor = 1
ElseIf faktor = 1 Then
faktor = 7
End If
Next

kontrollnummer = Right((10 - (Summa Mod 10)), 1)
%>
<%=kontrollnummer%>

[Bob Barrows [MVP]]

Kim wrote:

Hi, why doesn't this work inside a loop, gives me the wrong
"kontrollnummer" (increases it as the loop goes on)

<%
Dim kontrollnummer
Dim raknare
Dim Summa
Dim referens
referens = (rs_faktura.Fields.Item("customer_ID").Value) &
(rs_faktura.Fields.Item("bill_ID").Value)

Dim faktor
faktor = 7

For raknare = Len(referens) To 1 Step -1
Summa = Summa + Mid(referens, raknare, 1) * faktor
If faktor = 7 Then
faktor = 3
ElseIf faktor = 3 Then
faktor = 1
ElseIf faktor = 1 Then
faktor = 7
End If
Next

kontrollnummer = Right((10 - (Summa Mod 10)), 1)
%>
<%=kontrollnummer%>

Show us:
1. what the inputs look like
2. what the output is supposed to look like
3. what the output you are actually getting looks like

--
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[Kim]

Show us:

1. what the inputs look like
2. what the output is supposed to look like
3. what the output you are actually getting looks like

Input looks like forinstance 42146 (customer id 42 & bill id 146). Based on
this I need a check digit to the end at this 42146 that is calculated like:

the digits to be verified are multiplied by the weights 7, 3, 1, 7, 3,1 .
from the right to left. The multiplied sums are added up and the sum is
subtracted from then nearest figure ending in zero. The resulting difference
is the check digit which is entered as the last digit in the reference
number. If the difference is 10, the check digit is 0.

This is calculated properly by the code in my initial post if done once. But
when I put this into a loop only the first time are calculated properly,
thereafter the check digits turns out wrong.

[Bob Barrows [MVP]]

Kim wrote:

>Show us:
1. what the inputs look like
2. what the output is supposed to look like
3. what the output you are actually getting looks like

Input looks like forinstance 42146 (customer id 42 & bill id 146).
Based on this I need a check digit to the end at this 42146 that is
calculated like:
the digits to be verified are multiplied by the weights 7, 3, 1, 7,
3,1 . from the right to left. The multiplied sums are added up and
the sum is subtracted from then nearest figure ending in zero. The
resulting difference is the check digit which is entered as the last
digit in the reference number. If the difference is 10, the check
digit is 0.
This is calculated properly by the code in my initial post if done
once. But when I put this into a loop only the first time are
calculated properly, thereafter the check digits turns out wrong.

Again, please show us the inputs from say, the first three records, show us
what the desired output is supposed to look like from those three pieces of
data, and what you are actually getting. Looking at this, combined with your
above description, will help us analyze your code and figure out the
problem. A picture is worth a thousand words.
--
Microsoft MVP - ASP/ASP.NET
Please reply to the newsgroup. This email account is my spam trap so I
don't check it very often. If you must reply off-line, then remove the
"NO SPAM"

[Kim]

Again, please show us the inputs from say, the first three records, show

us what the desired output is supposed to look like from those three
pieces of data, and what you are actually getting. Looking at this,
combined with your above description, will help us analyze your code and
figure out the problem. A picture is worth a thousand words.

First record:
input = 3295
output= 32955 (ok)

second record:
input= 4296
output= 42966 (false, should be 42961)

third record:
input= 6297
output= 62976 (false, should be 62970)

[Bob Barrows [MVP]]

Kim wrote:

>Again, please show us the inputs from say, the first three records,
show us what the desired output is supposed to look like from those
three pieces of data, and what you are actually getting. Looking at
this, combined with your above description, will help us analyze
your code and figure out the problem. A picture is worth a thousand
words.

First record:
input = 3295
output= 32955 (ok)

second record:
input= 4296
output= 42966 (false, should be 42961)

third record:
input= 6297
output= 62976 (false, should be 62970)

OK, I'm back. I will play with this and get back to you.

--
Microsoft MVP - ASP/ASP.NET
Please reply to the newsgroup. This email account is my spam trap so I
don't check it very often. If you must reply off-line, then remove the
"NO SPAM"

[Bob Barrows [MVP]]

Kim wrote:

>Again, please show us the inputs from say, the first three records,
show us what the desired output is supposed to look like from those
three pieces of data, and what you are actually getting. Looking at
this, combined with your above description, will help us analyze
your code and figure out the problem. A picture is worth a thousand
words.

First record:
input = 3295
output= 32955 (ok)

second record:
input= 4296
output= 42966 (false, should be 42961)

third record:
input= 6297
output= 62976 (false, should be 62970)

OK, I could not use a recordset of course, so I put your inputs into an array and ran your code to get your results. I then did this to help you see what was going on:
<%
Dim kontrollnummer
Dim raknare
Dim Summa
Dim referens
dim ar, i
Dim faktor
ar=array("3295","4296","6297")
for i = 0 to 2
referens = ar(i)
faktor = 7
Response.Write "<hr><b>" & referens & "</b><br>"
Response.Write "<TABLE><tr><th>raknare</th><th>factor" & _
"</th><th>Summa (pre)</th><th>Summa (post)</th></tr>"
For raknare = Len(referens) To 1 Step -1
Response.Write "<tr><td>" & raknare & "</td>"
Response.Write "<td>" & faktor & "</td>"
Response.Write "<td>" & Summa & "</td>"
Summa = Summa + Mid(referens, raknare, 1) * faktor
Response.Write "<td>" & Summa & "</td></tr>"

If faktor = 7 Then
faktor = 3
ElseIf faktor = 3 Then
faktor = 1
ElseIf faktor = 1 Then
faktor = 7
End If
Next
Response.Write "</table>"
kontrollnummer = Right((10 - (Summa Mod 10)), 1)
Response.Write kontrollnummer & "<BR>"
next

%>
Running this code yields this result:

--------------------------------------------------------------------------------

3295

raknare factor Summa (pre) Summa (post)
4 7 35
3 3 35 62
2 1 62 64
1 7 64 85

5
--------------------------------------------------------------------------------

4296

raknare factor Summa (pre) Summa (post)
4 7 85 127
3 3 127 154
2 1 154 156
1 7 156 184

6
--------------------------------------------------------------------------------

6297

raknare factor Summa (pre) Summa (post)
4 7 184 233
3 3 233 260
2 1 260 262
1 7 262 304

6

As you should see from this, the problem is the failure to initialize Summa before each loop. Adding "Summa = 0" to the code, right below the "faktor=7" line yields the correct results:

--------------------------------------------------------------------------------
3295
raknare factor Summa (pre) Summa (post)
4 7 0 35
3 3 35 62
2 1 62 64
1 7 64 85
5

--------------------------------------------------------------------------------
4296
raknare factor Summa (pre) Summa (post)
4 7 0 42
3 3 42 69
2 1 69 71
1 7 71 99
1

--------------------------------------------------------------------------------
6297
raknare factor Summa (pre) Summa (post)
4 7 0 49
3 3 49 76
2 1 76 78
1 7 78 120
0


--
Microsoft MVP - ASP/ASP.NET
Please reply to the newsgroup. This email account is my spam trap so I
don't check it very often. If you must reply off-line, then remove the
"NO SPAM"

[Kim]

Oh man, that was an impressive answer. Not only did it work perfectly, it
also helped me understand the problem. Thank you so much, Bob.