# [EpiData-list] New user trying to implement a check algorithm

epidata-list at lists.umanitoba.ca epidata-list at lists.umanitoba.ca
Fri Apr 11 21:11:48 CDT 2008

```To fix this, define prn1 etc as an integer rather than _ ( _ means
string). You cannot do the arithmetic on prn as a string.These temporary
variables should be defined as global so that they don't appear in the data.

define checksum ## global
define prn1 # global

Then you can extract the digits thus:

prn1 = integer(copy(preQ2a,1,1))

I think you need to include the first digit in the algorithm as well. My
reading of the validation algorithm means you just need to check that
the total for all digits is a multiple of 10, so:

checkSum=prn1+pnr3+pnr4+pnr5+pnr6+pnr7+pnr8+pnr9+pnr10+pnr11+prn12
IF (checkSum mod 10) <> 0
THEN
HELP "felaktigt PersonNummer" TYPE=ERROR
GOTO preQ2
ENDIF

Jamie

Gustaf wrote:
> In this questionnaire, a 12 digit personal identification number
> should be entered. The first 8 digits of this number is the birthday,
> the following 3 digits carry some obscure meaning (gender being one of
> them), and the last digit is a control number calculated from the
> previous 11 digits by the luhn algorithm
> (http://en.wikipedia.org/wiki/Luhn_algorithm).
>
> when I try to use this check file, EipData doesn't like it,
> claiming the "FLOAT(copy(preQ2s,1,1))"-expressions are too wide. Any
> suggestions on how to solve this in a more elegant way?
>
> Many thanks in advance,
>
> Gustaf
>
> ------ Algorithm. "preQ2" is the variable name for the specific
> question, defined as a 12 digit number (############)------------
> preQ2
>
>     RANGE 199201010001 201801010001
>     DEFINE pnr1 _
>     DEFINE pnr2 _
>     DEFINE pnr3 _
>     DEFINE pnr4 _
>     DEFINE pnr5 _
>     DEFINE pnr6 _
>     DEFINE pnr7 _
>     DEFINE pnr8 _
>     DEFINE pnr9 _
>     DEFINE pnr10 _
>     DEFINE pnr11 _
>     DEFINE pnr12 _
>     DEFINE preQ2s ____________
>     DEFINE checkSum ##
>     preQ2s=string(preQ2)
>     pnr1=FLOAT(copy(preQ2s,1,1))
>     pnr2=FLOAT(copy(preQ2s,2,2))
>     pnr3=FLOAT(copy(preQ2s,3,3))
>     pnr4=FLOAT(copy(preQ2s,4,4))
>     pnr5=FLOAT(copy(preQ2s,5,5))
>     pnr6=FLOAT(copy(preQ2s,6,6))
>     pnr7=FLOAT(copy(preQ2s,7,7))
>     pnr8=FLOAT(copy(preQ2s,8,8))
>     pnr9=FLOAT(copy(preQ2s,9,9))
>     pnr10=FLOAT(copy(preQ2s,10,10))
>     pnr11=FLOAT(copy(preQ2s,11,11))
>     pnr12=FLOAT(copy(preQ2s,12,12))
>
>     IF (pnr3>4)
>         THEN pnr3=pnr3*2-9
>         ELSE pnr3=pnr3*2
>     ENDIF
>     IF (pnr5>4)
>         THEN pnr5=pnr5*2-9
>         ELSE pnr5=pnr5*2
>     ENDIF
>
>     IF (pnr7>4)
>         THEN pnr7=pnr7*2-9
>         ELSE pnr7=pnr7*2
>     ENDIF
>
>     IF (pnr9>4)
>         THEN pnr9=pnr9*2-9
>         ELSE pnr9=pnr9*2
>     ENDIF
>
>     IF (pnr11>4)
>         THEN pnr11=pnr11*2-9
>         ELSE pnr11=pnr11*2
>     ENDIF
>     checkSum=pnr3+pnr4+pnr5+pnr6+pnr7+pnr8+pnr9+pnr10+pnr11
>     IF (checkSum=10*int(checkSum))
>         THEN checkSum=checkSum/10
>         ELSE checkSum=10*(TRUNC(checkSum/10)+1)-checkSum
>     ENDIF
>     IF (pnr12<>checkSum)
>     THEN
>         HELP "felaktigt PersonNummer" TYPE=ERROR
>         GOTO preQ2
>     ENDIF
> END
>
>
```

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