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+--- Forum: General Software Library (/forum-13.html)
+--- Thread: (49G) Verhoeff Check Digit Programme (/thread-3989.html)
(49G) Verhoeff Check Digit Programme - Gerald H - 05-27-2015 06:44 AM
For positive integer input the programme returns the original input and the check digit.
eg For input
19530818
the programme returns
19530818
1
For more info on Verhoeff check digit see
http://en.wikipedia.org/wiki/Verhoeff_algorithm
Code:
::
CK1&Dispatch
# FF
::
MATRIX
MATRIX
Z1_
Z2_
Z3_
Z4_
Z5_
Z6_
Z7_
Z8_
Z9_
Z10_
;
MATRIX
Z2_
Z3_
Z4_
Z5_
Z1_
Z7_
Z8_
Z9_
Z10_
Z6_
;
MATRIX
Z3_
Z4_
Z5_
Z1_
Z2_
Z8_
Z9_
Z10_
Z6_
Z7_
;
MATRIX
Z4_
Z5_
Z1_
Z2_
Z3_
Z9_
Z10_
Z6_
Z7_
Z8_
;
MATRIX
Z5_
Z1_
Z2_
Z3_
Z4_
Z10_
Z6_
Z7_
Z8_
Z9_
;
MATRIX
Z6_
Z10_
Z9_
Z8_
Z7_
Z1_
Z5_
Z4_
Z3_
Z2_
;
MATRIX
Z7_
Z6_
Z10_
Z9_
Z8_
Z2_
Z1_
Z5_
Z4_
Z3_
;
MATRIX
Z8_
Z7_
Z6_
Z10_
Z9_
Z3_
Z2_
Z1_
Z5_
Z4_
;
MATRIX
Z9_
Z8_
Z7_
Z6_
Z10_
Z4_
Z3_
Z2_
Z1_
Z5_
;
MATRIX
Z10_
Z9_
Z8_
Z7_
Z6_
Z5_
Z4_
Z3_
Z2_
Z1_
;
;
BINT0
FPTR2 ^2LAMBIND
DUP
{
Z1_
Z5_
Z4_
Z3_
Z2_
Z7_
Z8_
Z9_
Z10_
Z6_
}
BINT10
DUP
#1+_ONE_DO
INDEX@
FPTR2 ^#>Z
SWAPLOOP
{}N
ROTDUP
PTR 2F3A3
COERCEDUP
BINT2
#<ITE
::
DROP
ROTROT2DROP
Z1_
FPTR2 ^QAdd
2GETLAM
;
::
DUP1PUTLAM_
ZERO_DO
Z10_
FPTR2 ^ZDIVext
ROT
4PICK
FPTR 7 17C
DUP4UNROLL
SWAP
FPTR2 ^Z2BIN
#1+
NTHCOMPDROP
4UNROLL
LOOP
3DROP
2GETLAM
1GETLAM
ONE_DO
3UNROLL
FPTR2 ^Z2BIN
#1-
#10*
SWAP
FPTR2 ^Z2BIN
#+
FPTR2 ^PULLEL[S]
SWAPLOOP
;
ABND
SWAP
FPTR2 ^Z>#
FPTR2 ^MATRIX-COL
SWAPDROP
FPTR2 ^MATRIX2LIST
Z1_
EQUALPOSCOMP
#1-
FPTR2 ^#>Z
;
;RE: HP 49G: Verhoeff Check Digit Programme - Thomas Klemm - 05-27-2015 09:29 PM
Very cool! This algorithm is based on multiplication in the dihedral group D5 which is not commutative. This allows to detect all transposition errors involving two adjacent digits.
There was a project where I decided to use this as the checksum digit for a numeric user ID which forced some batch-programmers to implement it in COBOL. They were not amused.
Cheers
Thomas