Damm algorithm: Difference between revisions
(→static table: simplified and optimized the code.) |
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112940 is not ok, check-digit should be 6 (instead of 0)</pre> |
112940 is not ok, check-digit should be 6 (instead of 0)</pre> |
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===static table=== |
=== static table === |
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Using a static table is over four times faster than manufacturing one. |
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<lang rexx>/*REXX pgm uses H. Michael Damm's algorithm to validate numbers with suffixed check sum.*/ |
<lang rexx>/*REXX pgm uses H. Michael Damm's algorithm to validate numbers with suffixed check sum.*/ |
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@.0= 0317598642; @.1= 7092154863; @.2= 4206871359; @.3= 1750983426; @.4= 6123045978 |
@.0= 0317598642; @.1= 7092154863; @.2= 4206871359; @.3= 1750983426; @.4= 6123045978 |
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Revision as of 01:31, 7 July 2020
You are encouraged to solve this task according to the task description, using any language you may know.
The Damm algorithm is a checksum algorithm which detects all single digit errors and adjacent transposition errors.
- Task
Verify the checksum, stored as last digit of an input.
11l
<lang 11l>V matrix = [
[0, 3, 1, 7, 5, 9, 8, 6, 4, 2], [7, 0, 9, 2, 1, 5, 4, 8, 6, 3], [4, 2, 0, 6, 8, 7, 1, 3, 5, 9], [1, 7, 5, 0, 9, 8, 3, 4, 2, 6], [6, 1, 2, 3, 0, 4, 5, 9, 7, 8], [3, 6, 7, 4, 2, 0, 9, 5, 8, 1], [5, 8, 6, 9, 7, 2, 0, 1, 3, 4], [8, 9, 4, 5, 3, 6, 2, 0, 1, 7], [9, 4, 3, 8, 6, 1, 7, 2, 0, 5], [2, 5, 8, 1, 4, 3, 6, 7, 9, 0]
]
F damm(Int num) -> Bool
V row = 0
L(digit) String(num)
row = :matrix[row][Int(digit)]
R row == 0
L(test) [5724, 5727, 112946]
print(test"\t Validates as: "damm(test))</lang>
- Output:
5724 Validates as: 1B 5727 Validates as: 0B 112946 Validates as: 1B
Ada
<lang Ada>with Ada.Text_IO;
procedure Damm_Algorithm is
function Damm (Input : in String) return Boolean
is
subtype Digit is Character range '0' .. '9';
Table : constant array (Digit, Digit) of Digit :=
(('0', '3', '1', '7', '5', '9', '8', '6', '4', '2'),
('7', '0', '9', '2', '1', '5', '4', '8', '6', '3'),
('4', '2', '0', '6', '8', '7', '1', '3', '5', '9'),
('1', '7', '5', '0', '9', '8', '3', '4', '2', '6'),
('6', '1', '2', '3', '0', '4', '5', '9', '7', '8'),
('3', '6', '7', '4', '2', '0', '9', '5', '8', '1'),
('5', '8', '6', '9', '7', '2', '0', '1', '3', '4'),
('8', '9', '4', '5', '3', '6', '2', '0', '1', '7'),
('9', '4', '3', '8', '6', '1', '7', '2', '0', '5'),
('2', '5', '8', '1', '4', '3', '6', '7', '9', '0'));
Intern : Digit := '0';
begin
for D of Input loop
Intern := Table (Intern, D);
end loop;
return Intern = '0';
end Damm;
procedure Put_Damm (Input : in String) is
use Ada.Text_IO;
begin
Put_Line ("Damm of " & Input & " validates as " & Damm (Input)'Image);
end Put_Damm;
begin
Put_Damm ("5724");
Put_Damm ("5727");
Put_Damm ("112946");
Put_Damm ("112949");
end Damm_Algorithm;</lang>
- Output:
Damm of 5724 validates as TRUE Damm of 5727 validates as FALSE Damm of 112946 validates as TRUE Damm of 112949 validates as FALSE
ALGOL 68
<lang algol68>BEGIN
# returns TRUE if the check digit of s is correct according to the Damm algorithm, #
# FALSE otherwise #
PROC has valid damm check digit = ( STRING s )BOOL:
BEGIN
# operation table - as per wikipedia example #
[,]INT operation table =
( [,]INT( ( 0, 3, 1, 7, 5, 9, 8, 6, 4, 2 )
, ( 7, 0, 9, 2, 1, 5, 4, 8, 6, 3 )
, ( 4, 2, 0, 6, 8, 7, 1, 3, 5, 9 )
, ( 1, 7, 5, 0, 9, 8, 3, 4, 2, 6 )
, ( 6, 1, 2, 3, 0, 4, 5, 9, 7, 8 )
, ( 3, 6, 7, 4, 2, 0, 9, 5, 8, 1 )
, ( 5, 8, 6, 9, 7, 2, 0, 1, 3, 4 )
, ( 8, 9, 4, 5, 3, 6, 2, 0, 1, 7 )
, ( 9, 4, 3, 8, 6, 1, 7, 2, 0, 5 )
, ( 2, 5, 8, 1, 4, 3, 6, 7, 9, 0 )
)
) [ AT 0, AT 0 ]
;
INT interim digit := 0;
FOR s pos FROM LWB s TO UPB s DO
INT next digit = ABS s[ s pos ] - ABS "0";
IF next digit < 0 OR next digit > 9 THEN
# invalid digit #
print( ( "Invalid damm digit: ", s[ s pos ], newline ) );
stop
ELSE
# have a valid digit #
interim digit := operation table[ interim digit, next digit ]
FI
OD;
interim digit = 0
END # has valid damm check digit # ;
# test the damm algorithm #
PROC test damm algorithm = ( STRING s, BOOL expected )VOID:
BEGIN
BOOL valid = has valid damm check digit( s );
print( ( "check digit of ", s, " is "
, IF valid THEN "valid" ELSE "invalid" FI
, IF valid = expected THEN "" ELSE " *** NOT AS EXPECTED" FI
, newline
)
)
END # test damm algorithm # ;
# test cases - as per other language samples #
test damm algorithm( "5724", TRUE );
test damm algorithm( "5727", FALSE );
test damm algorithm( "112946", TRUE )
END</lang>
- Output:
check digit of 5724 is valid check digit of 5727 is invalid check digit of 112946 is valid
AWK
<lang AWK># syntax: GAWK -f DAMM_ALGORITHM.AWK BEGIN {
damm_init()
leng = split("5724,5727,112946",arr,",") # test cases
for (i=1; i<=leng; i++) {
n = arr[i]
printf("%s %s\n",damm_check(n),n)
}
exit(0)
} function damm_check(n, a,i) {
a = 0
for (i=1; i<=length(n); i++) {
a = substr(damm[a],substr(n,i,1)+1,1)
}
return(a == 0 ? "T" : "F")
} function damm_init() {
- 0123456789
damm[0] = "0317598642" damm[1] = "7092154863" damm[2] = "4206871359" damm[3] = "1750983426" damm[4] = "6123045978" damm[5] = "3674209581" damm[6] = "5869720134" damm[7] = "8945362017" damm[8] = "9438617205" damm[9] = "2581436790"
}</lang>
- Output:
T 5724 F 5727 T 112946
C
<lang c>#include <stdbool.h>
- include <stddef.h>
- include <stdio.h>
bool damm(unsigned char *input, size_t length) {
static const unsigned char table[10][10] = {
{0, 3, 1, 7, 5, 9, 8, 6, 4, 2},
{7, 0, 9, 2, 1, 5, 4, 8, 6, 3},
{4, 2, 0, 6, 8, 7, 1, 3, 5, 9},
{1, 7, 5, 0, 9, 8, 3, 4, 2, 6},
{6, 1, 2, 3, 0, 4, 5, 9, 7, 8},
{3, 6, 7, 4, 2, 0, 9, 5, 8, 1},
{5, 8, 6, 9, 7, 2, 0, 1, 3, 4},
{8, 9, 4, 5, 3, 6, 2, 0, 1, 7},
{9, 4, 3, 8, 6, 1, 7, 2, 0, 5},
{2, 5, 8, 1, 4, 3, 6, 7, 9, 0},
};
unsigned char interim = 0;
for (size_t i = 0; i < length; i++) {
interim = table[interim][input[i]];
}
return interim == 0;
}
int main() {
unsigned char input[4] = {5, 7, 2, 4};
puts(damm(input, 4) ? "Checksum correct" : "Checksum incorrect");
return 0;
}</lang>
C#
<lang csharp>using System;
namespace DammAlgorithm {
class Program {
static int[,] table = {
{0, 3, 1, 7, 5, 9, 8, 6, 4, 2},
{7, 0, 9, 2, 1, 5, 4, 8, 6, 3},
{4, 2, 0, 6, 8, 7, 1, 3, 5, 9},
{1, 7, 5, 0, 9, 8, 3, 4, 2, 6},
{6, 1, 2, 3, 0, 4, 5, 9, 7, 8},
{3, 6, 7, 4, 2, 0, 9, 5, 8, 1},
{5, 8, 6, 9, 7, 2, 0, 1, 3, 4},
{8, 9, 4, 5, 3, 6, 2, 0, 1, 7},
{9, 4, 3, 8, 6, 1, 7, 2, 0, 5},
{2, 5, 8, 1, 4, 3, 6, 7, 9, 0},
};
static bool Damm(string s) {
int interim = 0;
foreach (char c in s) {
interim = table[interim, c - '0'];
}
return interim == 0;
}
static void Main(string[] args) {
int[] numbers = { 5724, 5727, 112946, 112949 };
foreach (int number in numbers) {
bool isValid = Damm(number.ToString());
if (isValid) {
Console.WriteLine("{0,6} is valid", number);
}
else {
Console.WriteLine("{0,6} is invalid", number);
}
}
}
}
}</lang>
- Output:
5724 is valid 5727 is invalid 112946 is valid 112949 is invalid
C++
<lang cpp>#include <sstream>
const int TABLE[][10] = { {0, 3, 1, 7, 5, 9, 8, 6, 4, 2}, {7, 0, 9, 2, 1, 5, 4, 8, 6, 3}, {4, 2, 0, 6, 8, 7, 1, 3, 5, 9}, {1, 7, 5, 0, 9, 8, 3, 4, 2, 6}, {6, 1, 2, 3, 0, 4, 5, 9, 7, 8}, {3, 6, 7, 4, 2, 0, 9, 5, 8, 1}, {5, 8, 6, 9, 7, 2, 0, 1, 3, 4}, {8, 9, 4, 5, 3, 6, 2, 0, 1, 7}, {9, 4, 3, 8, 6, 1, 7, 2, 0, 5}, {2, 5, 8, 1, 4, 3, 6, 7, 9, 0}, };
using std::string; bool damm(string s) { int interim = 0; for (char c : s) { interim = TABLE[interim][c - '0']; } return interim == 0; }
int main() { auto numbers = { 5724, 5727, 112946, 112949 }; for (int num : numbers) { using std::stringstream; stringstream ss; ss << num; bool isValid = damm(ss.str()); if (isValid) { printf("%6d is valid\n", num); } else { printf("%6d is invalid\n", num); } }
return 0; }</lang>
- Output:
5724 is valid 5727 is invalid 112946 is valid 112949 is invalid
Clojure
<lang clojure>(def tbl [[0 3 1 7 5 9 8 6 4 2]
[7 0 9 2 1 5 4 8 6 3]
[4 2 0 6 8 7 1 3 5 9]
[1 7 5 0 9 8 3 4 2 6]
[6 1 2 3 0 4 5 9 7 8]
[3 6 7 4 2 0 9 5 8 1]
[5 8 6 9 7 2 0 1 3 4]
[8 9 4 5 3 6 2 0 1 7]
[9 4 3 8 6 1 7 2 0 5]
[2 5 8 1 4 3 6 7 9 0]])
(defn damm? [digits]
(= 0 (reduce #(nth (nth tbl %1) %2) 0 (map #(Character/getNumericValue %) (seq digits)))))</lang>
- Output:
=> (damm? "5724") true => (damm? "5727") false => (damm? "112946") true
D
<lang D>import std.stdio;
auto table = [
[0, 3, 1, 7, 5, 9, 8, 6, 4, 2], [7, 0, 9, 2, 1, 5, 4, 8, 6, 3], [4, 2, 0, 6, 8, 7, 1, 3, 5, 9], [1, 7, 5, 0, 9, 8, 3, 4, 2, 6], [6, 1, 2, 3, 0, 4, 5, 9, 7, 8], [3, 6, 7, 4, 2, 0, 9, 5, 8, 1], [5, 8, 6, 9, 7, 2, 0, 1, 3, 4], [8, 9, 4, 5, 3, 6, 2, 0, 1, 7], [9, 4, 3, 8, 6, 1, 7, 2, 0, 5], [2, 5, 8, 1, 4, 3, 6, 7, 9, 0],
];
bool damm(string s) {
int interim = 0;
foreach (c; s) {
interim = table[interim][c - '0'];
}
return interim == 0;
}
void main() {
import std.conv : to;
auto numbers = [5724, 5727, 112946, 112949];
foreach (number; numbers) {
bool isValid = damm(number.to!string());
writef("%6d is ", number);
if (isValid) {
writeln("valid");
} else {
writeln("invalid");
}
}
}</lang>
- Output:
5724 is valid 5727 is invalid 112946 is valid 112949 is invalid
F#
<lang fsharp>open System
let TABLE = [|
[|0; 3; 1; 7; 5; 9; 8; 6; 4; 2|]; [|7; 0; 9; 2; 1; 5; 4; 8; 6; 3|]; [|4; 2; 0; 6; 8; 7; 1; 3; 5; 9|]; [|1; 7; 5; 0; 9; 8; 3; 4; 2; 6|]; [|6; 1; 2; 3; 0; 4; 5; 9; 7; 8|]; [|3; 6; 7; 4; 2; 0; 9; 5; 8; 1|]; [|5; 8; 6; 9; 7; 2; 0; 1; 3; 4|]; [|8; 9; 4; 5; 3; 6; 2; 0; 1; 7|]; [|9; 4; 3; 8; 6; 1; 7; 2; 0; 5|]; [|2; 5; 8; 1; 4; 3; 6; 7; 9; 0|];
|]
let damm str =
let rec helper (v:string) interim =
if v.Length = 0 then 0 = interim
else helper (v.Substring(1)) (TABLE.[interim].[(int (v.[0])) - (int '0')])
helper str 0
[<EntryPoint>] let main _ =
let numbers = [|5724; 5727; 112946; 112949|]
for number in numbers do
let isValid = damm (number.ToString())
if isValid then
printfn "%6d is valid" number
else
printfn "%6d is invalid" number
0 // return an integer exit code
</lang>
- Output:
5724 is valid 5727 is invalid 112946 is valid 112949 is invalid
Factor
<lang factor>USING: interpolate kernel math math.parser qw sequences ;
CONSTANT: table {
{ 0 3 1 7 5 9 8 6 4 2 }
{ 7 0 9 2 1 5 4 8 6 3 }
{ 4 2 0 6 8 7 1 3 5 9 }
{ 1 7 5 0 9 8 3 4 2 6 }
{ 6 1 2 3 0 4 5 9 7 8 }
{ 3 6 7 4 2 0 9 5 8 1 }
{ 5 8 6 9 7 2 0 1 3 4 }
{ 8 9 4 5 3 6 2 0 1 7 }
{ 9 4 3 8 6 1 7 2 0 5 }
{ 2 5 8 1 4 3 6 7 9 0 }
}
- damm? ( str -- ? )
0 [ digit> swap table nth nth ] reduce zero? ;
qw{ 5724 5727 112946 112949 } [ dup damm? "" "in" ? [I ${} is ${}validI] nl ] each</lang>
- Output:
5724 is valid 5727 is invalid 112946 is valid 112949 is invalid
Fortran
Thanks to the ability standardised in F90 to define an array with a lower bound other than one, this can be achieved without the need for annoying offsets, as in A(i + 1) instead of just A(i). However, right from the start, Fortran has stored arrays in column-major order, so statements that initialise two-dimensional arrays via a list of consecutive values can look odd when they are nicely laid out, because they will have to be be in transposed order. Alternatively, if the layout is the same as the expected (row,column) usage, the actual usage of the array will have to be (column,row). Rather than transpose a ten by ten matrix, this is the approach here. The continuation column has the (apparent) row count, but row zero can't have the digit zero in the continuation column as this is taken to be equivalent to a space (meaning "no continuation") just in case it is used for the first line of a statement to be continued. However, the letter o will do instead. A capital O looks too much like a 0...
Possibly a more useful function would be one that returned the check digit that must be appended to a sequence to provide the full sequence, as when preparing a checksummed sequence for output. For checking input, such a function would be applied to all but the last digit of the suspect sequence, and its result compared to the supplied last digit. But for simplicity here, all that is reported is "good" or "bad", without hints as to what would have been good. <lang Fortran> LOGICAL FUNCTION DAMM(DIGIT) !Check that a sequence of digits checks out.. Calculates according to the method of H. Michael Damm, described in 2004.
CHARACTER*(*) DIGIT !A sequence of digits only.
INTEGER*1 OPTABLE(0:9,0:9) !The special "Operation table" of the method.
PARAMETER (OPTABLE = (/ !A set of constants...
o 0, 3, 1, 7, 5, 9, 8, 6, 4, 2, ! CAREFUL!
1 7, 0, 9, 2, 1, 5, 4, 8, 6, 3, !Fortran stores arrays in column-major order.
2 4, 2, 0, 6, 8, 7, 1, 3, 5, 9, !Despite the manifest row and column layout apparent here
3 1, 7, 5, 0, 9, 8, 3, 4, 2, 6, !This sequence of consecutive items will go into storage order.
4 6, 1, 2, 3, 0, 4, 5, 9, 7, 8, !The table resulting from this sequence of constants
5 3, 6, 7, 4, 2, 0, 9, 5, 8, 1, !Will appear to be transposed if referenced as (row,column)
6 5, 8, 6, 9, 7, 2, 0, 1, 3, 4, !What appears to be row=6 column=1 (counting from zero)
7 8, 9, 4, 5, 3, 6, 2, 0, 1, 7, !is to be accessed as OPTABLE(1,6) = 8, not OPTABLE(6,1)
8 9, 4, 3, 8, 6, 1, 7, 2, 0, 5, !Storage order is (0,0), (1,0), (2,0), ... (9,0)
9 2, 5, 8, 1, 4, 3, 6, 7, 9, 0/)) !Followed by (0,1), (1,1), (2,1), ... (9,1)
INTEGER I,D,ID !Assistants.
ID = 0 !Here we go.
DO I = 1,LEN(DIGIT) !Step through the text.
D = ICHAR(DIGIT(I:I)) - ICHAR("0") !Convert to an integer. (ASCII or EBCDIC)
IF (D.LT.0 .OR. D.GT.9) STOP "DAMM! Not a digit!" !This shouldn't happen!
ID = OPTABLE(D,ID) !Transposed: D is the column index and ID the row.
END DO !On to the next.
DAMM = ID .EQ. 0 !Somewhere, a check digit should ensure this.
END FUNCTION DAMM !Simple, fast, and alas, rarely used.
LOGICAL DAMM !Not a default type.
WRITE (6,*) DAMM("5724"),"5724"
WRITE (6,*) DAMM("5727"),"5727"
WRITE (6,*) DAMM("112946"),"112946"
END</lang>
Output:
T 5724 F 5727 T 112946
FreeBASIC
<lang freebasic>' version 04-07-2018 ' compile with: fbc -s console
Function Damm(digit_str As String) As UInteger
Dim As UInteger table(10,10) => { { 0, 3, 1, 7, 5, 9, 8, 6, 4, 2 } , _
{ 7, 0, 9, 2, 1, 5, 4, 8, 6, 3 } , { 4, 2, 0, 6, 8, 7, 1, 3, 5, 9 } , _
{ 1, 7, 5, 0, 9, 8, 3, 4, 2, 6 } , { 6, 1, 2, 3, 0, 4, 5, 9, 7, 8 } , _
{ 3, 6, 7, 4, 2, 0, 9, 5, 8, 1 } , { 5, 8, 6, 9, 7, 2, 0, 1, 3, 4 } , _
{ 8, 9, 4, 5, 3, 6, 2, 0, 1, 7 } , { 9, 4, 3, 8, 6, 1, 7, 2, 0, 5 } , _
{ 2, 5, 8, 1, 4, 3, 6, 7, 9, 0 } }
Dim As UInteger i, col_i, old_row_i, new_row_i
For i = 0 To Len(digit_str) -1
col_i = digit_str[i] - Asc("0")
new_row_i = table(old_row_i, col_i)
old_row_i = new_row_i
Next
Return new_row_i
End Function
' ------=< MAIN >=------
Data "5724", "5727", "112946", ""
Dim As UInteger checksum, t Dim As String test_string
Do
Read test_string If test_string = "" Then Exit Do Print "Checksum test: ";test_string;
checksum = Damm(test_string)
If checksum = 0 Then
Print " is valid"
Else
Print " is invalid"
End If
Loop
' empty keyboard buffer While Inkey <> "" : Wend Print : Print "hit any key to end program" Sleep End</lang>
- Output:
Checksum test: 5724 is valid Checksum test: 5727 is invalid Checksum test: 112946 is valid
Fōrmulæ
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Go
<lang go>package main
import "fmt"
var table = [10][10]byte{
{0, 3, 1, 7, 5, 9, 8, 6, 4, 2},
{7, 0, 9, 2, 1, 5, 4, 8, 6, 3},
{4, 2, 0, 6, 8, 7, 1, 3, 5, 9},
{1, 7, 5, 0, 9, 8, 3, 4, 2, 6},
{6, 1, 2, 3, 0, 4, 5, 9, 7, 8},
{3, 6, 7, 4, 2, 0, 9, 5, 8, 1},
{5, 8, 6, 9, 7, 2, 0, 1, 3, 4},
{8, 9, 4, 5, 3, 6, 2, 0, 1, 7},
{9, 4, 3, 8, 6, 1, 7, 2, 0, 5},
{2, 5, 8, 1, 4, 3, 6, 7, 9, 0},
}
func damm(input string) bool {
var interim byte
for _, c := range []byte(input) {
interim = table[interim][c-'0']
}
return interim == 0
}
func main() {
for _, s := range []string{"5724", "5727", "112946", "112949"} {
fmt.Printf("%6s %t\n", s, damm(s))
}
}</lang>
- Output:
5724 true 5727 false 112946 true 112949 false
Groovy
<lang groovy>class DammAlgorithm {
private static final int[][] TABLE = [
[0, 3, 1, 7, 5, 9, 8, 6, 4, 2],
[7, 0, 9, 2, 1, 5, 4, 8, 6, 3],
[4, 2, 0, 6, 8, 7, 1, 3, 5, 9],
[1, 7, 5, 0, 9, 8, 3, 4, 2, 6],
[6, 1, 2, 3, 0, 4, 5, 9, 7, 8],
[3, 6, 7, 4, 2, 0, 9, 5, 8, 1],
[5, 8, 6, 9, 7, 2, 0, 1, 3, 4],
[8, 9, 4, 5, 3, 6, 2, 0, 1, 7],
[9, 4, 3, 8, 6, 1, 7, 2, 0, 5],
[2, 5, 8, 1, 4, 3, 6, 7, 9, 0],
]
private static boolean damm(String s) {
int interim = 0
for (char c : s.toCharArray()) interim = TABLE[interim][c - ('0' as Character)]
return interim == 0
}
static void main(String[] args) {
int[] numbers = [5724, 5727, 112946, 112949]
for (Integer number : numbers) {
boolean isValid = damm(number.toString())
if (isValid) {
System.out.printf("%6d is valid\n", number)
} else {
System.out.printf("%6d is invalid\n", number)
}
}
}
}</lang>
- Output:
5724 is valid 5727 is invalid 112946 is valid 112949 is invalid
J
Solution: <lang j>OpTbl=: _99 ". ];._2 noun define 0 3 1 7 5 9 8 6 4 2 7 0 9 2 1 5 4 8 6 3 4 2 0 6 8 7 1 3 5 9 1 7 5 0 9 8 3 4 2 6 6 1 2 3 0 4 5 9 7 8 3 6 7 4 2 0 9 5 8 1 5 8 6 9 7 2 0 1 3 4 8 9 4 5 3 6 2 0 1 7 9 4 3 8 6 1 7 2 0 5 2 5 8 1 4 3 6 7 9 0 )
getdigits=: 10&#.inv
getDamm=: verb define
row=. 0
for_digit. getdigits y do.
row=. OpTbl {~ <row,digit
end.
)
checkDamm=: 0 = getDamm</lang> Example Usage: <lang j> checkDamm&> 5724 5727 112946 1 0 1</lang>
Java
<lang Java>public class DammAlgorithm {
private static final int[][] table = {
{0, 3, 1, 7, 5, 9, 8, 6, 4, 2},
{7, 0, 9, 2, 1, 5, 4, 8, 6, 3},
{4, 2, 0, 6, 8, 7, 1, 3, 5, 9},
{1, 7, 5, 0, 9, 8, 3, 4, 2, 6},
{6, 1, 2, 3, 0, 4, 5, 9, 7, 8},
{3, 6, 7, 4, 2, 0, 9, 5, 8, 1},
{5, 8, 6, 9, 7, 2, 0, 1, 3, 4},
{8, 9, 4, 5, 3, 6, 2, 0, 1, 7},
{9, 4, 3, 8, 6, 1, 7, 2, 0, 5},
{2, 5, 8, 1, 4, 3, 6, 7, 9, 0},
};
private static boolean damm(String s) {
int interim = 0;
for (char c : s.toCharArray()) interim = table[interim][c - '0'];
return interim == 0;
}
public static void main(String[] args) {
int[] numbers = {5724, 5727, 112946, 112949};
for (Integer number : numbers) {
boolean isValid = damm(number.toString());
if (isValid) {
System.out.printf("%6d is valid\n", number);
} else {
System.out.printf("%6d is invalid\n", number);
}
}
}
}</lang>
- Output:
5724 is valid 5727 is invalid 112946 is valid 112949 is invalid
Julia
<lang julia>function checkdigit(n)
matrix = (
(0, 3, 1, 7, 5, 9, 8, 6, 4, 2),
(7, 0, 9, 2, 1, 5, 4, 8, 6, 3),
(4, 2, 0, 6, 8, 7, 1, 3, 5, 9),
(1, 7, 5, 0, 9, 8, 3, 4, 2, 6),
(6, 1, 2, 3, 0, 4, 5, 9, 7, 8),
(3, 6, 7, 4, 2, 0, 9, 5, 8, 1),
(5, 8, 6, 9, 7, 2, 0, 1, 3, 4),
(8, 9, 4, 5, 3, 6, 2, 0, 1, 7),
(9, 4, 3, 8, 6, 1, 7, 2, 0, 5),
(2, 5, 8, 1, 4, 3, 6, 7, 9, 0))
row = 0
for d in string(n)
row = matrix[row + 1][d - '0' + 1]
end
return row
end
foreach(i -> println("$i validates as: ", checkdigit(string(i)) == 0), [5724, 5727, 112946])
</lang>
- Output:
5724 validates as: true 5727 validates as: false 112946 validates as: true
Kotlin
<lang scala>// version 1.1.2
val table = arrayOf(
intArrayOf(0, 3, 1, 7, 5, 9, 8, 6, 4, 2), intArrayOf(7, 0, 9, 2, 1, 5, 4, 8, 6, 3), intArrayOf(4, 2, 0, 6, 8, 7, 1, 3, 5, 9), intArrayOf(1, 7, 5, 0, 9, 8, 3, 4, 2, 6), intArrayOf(6, 1, 2, 3, 0, 4, 5, 9, 7, 8), intArrayOf(3, 6, 7, 4, 2, 0, 9, 5, 8, 1), intArrayOf(5, 8, 6, 9, 7, 2, 0, 1, 3, 4), intArrayOf(8, 9, 4, 5, 3, 6, 2, 0, 1, 7), intArrayOf(9, 4, 3, 8, 6, 1, 7, 2, 0, 5), intArrayOf(2, 5, 8, 1, 4, 3, 6, 7, 9, 0)
)
fun damm(s: String): Boolean {
var interim = 0 for (c in s) interim = table[interim][c - '0'] return interim == 0
}
fun main(args: Array<String>) {
val numbers = intArrayOf(5724, 5727, 112946, 112949)
for (number in numbers) {
val isValid = damm(number.toString())
println("${"%6d".format(number)} is ${if (isValid) "valid" else "invalid"}")
}
}</lang>
- Output:
5724 is valid 5727 is invalid 112946 is valid 112949 is invalid
Lua
<lang lua>local tab = {
{0,3,1,7,5,9,8,6,4,2}, {7,0,9,2,1,5,4,8,6,3},
{4,2,0,6,8,7,1,3,5,9}, {1,7,5,0,9,8,3,4,2,6},
{6,1,2,3,0,4,5,9,7,8}, {3,6,7,4,2,0,9,5,8,1},
{5,8,6,9,7,2,0,1,3,4}, {8,9,4,5,3,6,2,0,1,7},
{9,4,3,8,6,1,7,2,0,5}, {2,5,8,1,4,3,6,7,9,0}
} function check( n )
local idx, a = 0, tonumber( n:sub( 1, 1 ) )
for i = 1, #n do
a = tonumber( n:sub( i, i ) )
if a == nil then return false end
idx = tab[idx + 1][a + 1]
end
return idx == 0
end local n, r while( true ) do
io.write( "Enter the number to check: " ) n = io.read(); if n == "0" then break end r = check( n ); io.write( n, " is " ) if not r then io.write( "in" ) end io.write( "valid!\n" )
end</lang>
- Output:
Enter the number to check: 5724 5724 is valid! Enter the number to check: 5727 5727 is invalid! Enter the number to check: 112946 112946 is valid! Enter the number to check: 0
Modula-2
<lang modula2>MODULE DammAlgorithm;
FROM FormatString IMPORT FormatString;
FROM Terminal IMPORT WriteString,WriteLn,ReadChar;
TYPE TA = ARRAY[0..9],[0..9] OF INTEGER; CONST table = TA{
{0, 3, 1, 7, 5, 9, 8, 6, 4, 2},
{7, 0, 9, 2, 1, 5, 4, 8, 6, 3},
{4, 2, 0, 6, 8, 7, 1, 3, 5, 9},
{1, 7, 5, 0, 9, 8, 3, 4, 2, 6},
{6, 1, 2, 3, 0, 4, 5, 9, 7, 8},
{3, 6, 7, 4, 2, 0, 9, 5, 8, 1},
{5, 8, 6, 9, 7, 2, 0, 1, 3, 4},
{8, 9, 4, 5, 3, 6, 2, 0, 1, 7},
{9, 4, 3, 8, 6, 1, 7, 2, 0, 5},
{2, 5, 8, 1, 4, 3, 6, 7, 9, 0}
};
PROCEDURE Damm(s : ARRAY OF CHAR) : BOOLEAN; VAR interim,i : INTEGER; BEGIN
interim := 0;
i := 0;
WHILE s[i] # 0C DO
interim := table[interim,INT(s[i])-INT('0')];
INC(i);
END;
RETURN interim=0;
END Damm;
PROCEDURE Print(number : INTEGER); VAR
isValid : BOOLEAN; buf : ARRAY[0..16] OF CHAR;
BEGIN
FormatString("%i", buf, number);
isValid := Damm(buf);
WriteString(buf);
IF isValid THEN
WriteString(" is valid");
ELSE
WriteString(" is invalid");
END;
WriteLn;
END Print;
BEGIN
Print(5724); Print(5727); Print(112946); Print(112949);
ReadChar;
END DammAlgorithm.</lang>
Objeck
<lang objeck>class DammAlgorithm {
@table : static : Int[,];
function : Main(args : String[]) ~ Nil {
@table := [
[0, 3, 1, 7, 5, 9, 8, 6, 4, 2]
[7, 0, 9, 2, 1, 5, 4, 8, 6, 3]
[4, 2, 0, 6, 8, 7, 1, 3, 5, 9]
[1, 7, 5, 0, 9, 8, 3, 4, 2, 6]
[6, 1, 2, 3, 0, 4, 5, 9, 7, 8]
[3, 6, 7, 4, 2, 0, 9, 5, 8, 1]
[5, 8, 6, 9, 7, 2, 0, 1, 3, 4]
[8, 9, 4, 5, 3, 6, 2, 0, 1, 7]
[9, 4, 3, 8, 6, 1, 7, 2, 0, 5]
[2, 5, 8, 1, 4, 3, 6, 7, 9, 0]];
numbers := [ 5724, 5727, 112946, 112949 ];
each (i : numbers) {
number := numbers[i];
isValid := Damm(number->ToString());
if (isValid) {
"{$number} is valid"->PrintLine();
}
else {
"{$number} is invalid"->PrintLine();
};
};
}
function : Damm(s : String) ~ Bool {
interim := 0;
each (i : s) {
interim := @table[interim, s->Get(i) - '0'];
};
return interim = 0;
}
}</lang>
- Output:
5724 is valid 5727 is invalid 112946 is valid 112949 is invalid
Pascal
nearly copy&paste
<lang pascal>program DammAlgorithm; uses
sysutils;
TYPE TA = ARRAY[0..9,0..9] OF UInt8; CONST table : TA =
((0,3,1,7,5,9,8,6,4,2),
(7,0,9,2,1,5,4,8,6,3),
(4,2,0,6,8,7,1,3,5,9),
(1,7,5,0,9,8,3,4,2,6),
(6,1,2,3,0,4,5,9,7,8),
(3,6,7,4,2,0,9,5,8,1),
(5,8,6,9,7,2,0,1,3,4),
(8,9,4,5,3,6,2,0,1,7),
(9,4,3,8,6,1,7,2,0,5),
(2,5,8,1,4,3,6,7,9,0));
function Damm(s : string) : BOOLEAN; VAR
interim,i : UInt8;
BEGIN
interim := 0;
i := 1;
WHILE i <= length(s) DO
Begin
interim := table[interim,ORD(s[i])-ORD('0')];
INC(i);
END;
Damm := interim=0;
END;
PROCEDURE Print(number : Uint32); VAR
isValid : BOOLEAN; buf :string;
BEGIN
buf := IntToStr(number);
isValid := Damm(buf);
Write(buf);
IF isValid THEN
Write(' is valid')
ELSE
Write(' is invalid');
WriteLn;
END;
BEGIN
Print(5724); Print(5727); Print(112946); Print(112949); Readln;
END.</lang>
- Output:
5724 is valid 5727 is invalid 112946 is valid 112949 is invalid
Perl
<lang perl>sub damm {
my(@digits) = split , @_[0];
my @tbl =([< 0 3 1 7 5 9 8 6 4 2 >],
[< 7 0 9 2 1 5 4 8 6 3 >],
[< 4 2 0 6 8 7 1 3 5 9 >],
[< 1 7 5 0 9 8 3 4 2 6 >],
[< 6 1 2 3 0 4 5 9 7 8 >],
[< 3 6 7 4 2 0 9 5 8 1 >],
[< 5 8 6 9 7 2 0 1 3 4 >],
[< 8 9 4 5 3 6 2 0 1 7 >],
[< 9 4 3 8 6 1 7 2 0 5 >],
[< 2 5 8 1 4 3 6 7 9 0 >]
);
my $row = 0;
for my $col (@digits) { $row = $tbl[$row][$col] }
not $row
}
for (5724, 5727, 112946) {
print "$_:\tChecksum digit @{[damm($_) ? : 'in']}correct.\n"
}</lang>
- Output:
5724: Checksum digit correct. 5727: Checksum digit incorrect. 112946: Checksum digit correct.
Phix
As phix uses 1-based indexes, 1 must be added to the operation table, and validity is given by ending on one, rather than zero. <lang Phix>constant tbl = sq_add(1,{{0, 3, 1, 7, 5, 9, 8, 6, 4, 2},
{7, 0, 9, 2, 1, 5, 4, 8, 6, 3},
{4, 2, 0, 6, 8, 7, 1, 3, 5, 9},
{1, 7, 5, 0, 9, 8, 3, 4, 2, 6},
{6, 1, 2, 3, 0, 4, 5, 9, 7, 8},
{3, 6, 7, 4, 2, 0, 9, 5, 8, 1},
{5, 8, 6, 9, 7, 2, 0, 1, 3, 4},
{8, 9, 4, 5, 3, 6, 2, 0, 1, 7},
{9, 4, 3, 8, 6, 1, 7, 2, 0, 5},
{2, 5, 8, 1, 4, 3, 6, 7, 9, 0}})
function damm(string s)
integer interim = 1
for i=1 to length(s) do
integer nxt = s[i]-'0'+1
if nxt<1 or nxt>10 then return 0 end if
interim = tbl[interim][nxt]
end for
return interim == 1
end function
constant tests = {"5724", "5727", "112946", "112949"} for i=1 to length(tests) do
string ti = tests[i]
printf(1,"%7s is %svalid\n",{ti,iff(damm(ti)?"":"in")})
end for</lang>
- Output:
5724 is valid 5727 is invalid 112946 is valid 112949 is invalid
PicoLisp
<lang PicoLisp>(setq *D
(quote
(0 3 1 7 5 9 8 6 4 2)
(7 0 9 2 1 5 4 8 6 3)
(4 2 0 6 8 7 1 3 5 9)
(1 7 5 0 9 8 3 4 2 6)
(6 1 2 3 0 4 5 9 7 8)
(3 6 7 4 2 0 9 5 8 1)
(5 8 6 9 7 2 0 1 3 4)
(8 9 4 5 3 6 2 0 1 7)
(9 4 3 8 6 1 7 2 0 5)
(2 5 8 1 4 3 6 7 9 0) ) )
(de damm? (N)
(let R 1
(for N (mapcar format (chop N))
(setq R (inc (get *D R (inc N)))) )
(= 1 R) ) )
(println (damm? 5724)) (println (damm? 5727)) (println (damm? 112946)) (println (damm? 112940))</lang>
- Output:
T NIL T NIL
Python
<lang Python>def damm(num: int) -> bool:
row = 0
for digit in str(num):
row = _matrix[row][int(digit)]
return row == 0
_matrix = (
(0, 3, 1, 7, 5, 9, 8, 6, 4, 2), (7, 0, 9, 2, 1, 5, 4, 8, 6, 3), (4, 2, 0, 6, 8, 7, 1, 3, 5, 9), (1, 7, 5, 0, 9, 8, 3, 4, 2, 6), (6, 1, 2, 3, 0, 4, 5, 9, 7, 8), (3, 6, 7, 4, 2, 0, 9, 5, 8, 1), (5, 8, 6, 9, 7, 2, 0, 1, 3, 4), (8, 9, 4, 5, 3, 6, 2, 0, 1, 7), (9, 4, 3, 8, 6, 1, 7, 2, 0, 5), (2, 5, 8, 1, 4, 3, 6, 7, 9, 0)
)
if __name__ == '__main__':
for test in [5724, 5727, 112946]:
print(f'{test}\t Validates as: {damm(test)}')</lang>
- Output:
5724 Validates as: True 5727 Validates as: False 112946 Validates as: True
Racket
<lang racket>#lang racket/base (require racket/match)
(define operation-table
#(#(0 3 1 7 5 9 8 6 4 2) #(7 0 9 2 1 5 4 8 6 3) #(4 2 0 6 8 7 1 3 5 9) #(1 7 5 0 9 8 3 4 2 6) #(6 1 2 3 0 4 5 9 7 8) #(3 6 7 4 2 0 9 5 8 1) #(5 8 6 9 7 2 0 1 3 4) #(8 9 4 5 3 6 2 0 1 7) #(9 4 3 8 6 1 7 2 0 5) #(2 5 8 1 4 3 6 7 9 0)))
(define (integer->digit-list n)
(let loop ((n n) (a null)) (if (zero? n) a (let-values (([q r] (quotient/remainder n 10))) (loop q (cons r a))))))
(define/match (check-digit n)
[((list ds ...))
(foldl
(λ (d interim)
(vector-ref (vector-ref operation-table interim) d))
0 ds)]
[((? integer? i))
(check-digit (integer->digit-list i))])
(define/match (valid-number? n)
[((? integer? i)) (valid-number? (integer->digit-list i))] [((list ds ...)) (zero? (check-digit ds))])
(module+ test
(require rackunit) (check-equal? (integer->digit-list 572) '(5 7 2)) (check-equal? (check-digit 572) 4) (check-equal? (check-digit '(5 7 2)) 4) (check-true (valid-number? 5724)) (check-false (valid-number? 5274)) (check-true (valid-number? 112946)))</lang>
No output from checks means that all tests passed.
Raku
(formerly Perl 6)
<lang perl6>sub damm ( *@digits ) {
my @tbl = [0, 3, 1, 7, 5, 9, 8, 6, 4, 2],
[7, 0, 9, 2, 1, 5, 4, 8, 6, 3],
[4, 2, 0, 6, 8, 7, 1, 3, 5, 9],
[1, 7, 5, 0, 9, 8, 3, 4, 2, 6],
[6, 1, 2, 3, 0, 4, 5, 9, 7, 8],
[3, 6, 7, 4, 2, 0, 9, 5, 8, 1],
[5, 8, 6, 9, 7, 2, 0, 1, 3, 4],
[8, 9, 4, 5, 3, 6, 2, 0, 1, 7],
[9, 4, 3, 8, 6, 1, 7, 2, 0, 5],
[2, 5, 8, 1, 4, 3, 6, 7, 9, 0];
my $row = 0;
for @digits -> $col { $row = @tbl[$row][$col] }
not $row
}
- Testing
for 5724, 5727, 112946 {
say "$_:\tChecksum digit { damm( $_.comb ) ?? !! 'in' }correct."
}</lang>
- Output:
5724: Checksum digit correct. 5727: Checksum digit incorrect. 112946: Checksum digit correct.
REXX
manufactured table
<lang rexx>/* REXX */ Call init Call test 5724 Call test 5727 Call test 112946 Call test 112940 Exit
test: Parse Arg number int_digit=0 Do p=1 To length(number)
d=substr(number,p,1) int_digit=grid.int_digit.d If p<length(number) Then cd=int_digit End
If int_digit=0 Then
Say number 'is ok'
Else
Say number 'is not ok, check-digit should be' cd '(instead of' d')'
Return
init: i=-2 Call setup '* 0 1 2 3 4 5 6 7 8 9' Call setup '0 0 3 1 7 5 9 8 6 4 2' Call setup '1 7 0 9 2 1 5 4 8 6 3' Call setup '2 4 2 0 6 8 7 1 3 5 9' Call setup '3 1 7 5 0 9 8 3 4 2 6' Call setup '4 6 1 2 3 0 4 5 9 7 8' Call setup '5 3 6 7 4 2 0 9 5 8 1' Call setup '6 5 8 6 9 7 2 0 1 3 4' Call setup '7 8 9 4 5 3 6 2 0 1 7' Call setup '8 9 4 3 8 6 1 7 2 0 5' Call setup '9 2 5 8 1 4 3 6 7 9 0' Return setup:
Parse Arg list i=i+1 Do col=-1 To 9 grid.i.col=word(list,col+2) End Return</lang>
- Output:
5724 is ok 5727 is not ok, check-digit should be 4 (instead of 7) 112946 is ok 112940 is not ok, check-digit should be 6 (instead of 0)
static table
Using a static table is over four times faster than manufacturing one. <lang rexx>/*REXX pgm uses H. Michael Damm's algorithm to validate numbers with suffixed check sum.*/
@.0= 0317598642; @.1= 7092154863; @.2= 4206871359; @.3= 1750983426; @.4= 6123045978 @.5= 3674209581; @.6= 5869720134; @.7= 8945362017; @.8= 9438617205; @.9= 2581436790
call Damm 5724, 5727, 112946, 112940 /*invoke Damm's algorithm for some #'s.*/ exit 0 /*stick a fork in it, we're all done. */ /*──────────────────────────────────────────────────────────────────────────────────────*/ Damm: do j=1 for arg(); x= arg(j); $= 0; z= right(x, 1)
do p=1 for length(x); g=$; $= substr(@.$, 1 + substr(x, p, 1), 1)
end /*p*/
if $==0 then say ' valid checksum digit ' z " for " x
else say ' invalid checksum digit ' z " for " x ' (should be' g")"
end /*j*/; return</lang>
- output when using the (internal) default inputs:
valid checksum digit 4 for 5724 invalid checksum digit 7 for 5727 (should be 4) valid checksum digit 6 for 112946 invalid checksum digit 0 for 112940 (should be 6)
Ring
<lang ring># Project : Damm algorithm
matrix = [[0, 3, 1, 7, 5, 9, 8, 6, 4, 2],
[7, 0, 9, 2, 1, 5, 4, 8, 6, 3],
[4, 2, 0, 6, 8, 7, 1, 3, 5, 9],
[1, 7, 5, 0, 9, 8, 3, 4, 2, 6],
[6, 1, 2, 3, 0, 4, 5, 9, 7, 8],
[3, 6, 7, 4, 2, 0, 9, 5, 8, 1],
[5, 8, 6, 9, 7, 2, 0, 1, 3, 4],
[8, 9, 4, 5, 3, 6, 2, 0, 1, 7],
[9, 4, 3, 8, 6, 1, 7, 2, 0, 5],
[2, 5, 8, 1, 4, 3, 6, 7, 9, 0]]
see "5724" + encode(5724 ) + nl see "5727" + encode(5727 ) + nl see "112946" + encode(112946) + nl
func encode(n)
check = 0
for d in string(n)
check = matrix[check+1][d-'0'+1]
next
if check = 0
return " is valid"
else
return " is invalid"
ok</lang>
Output:
5724 is valid 5727 is invalid 112946 is valid
Ruby
<lang ruby>def dammCheck( nbr )
idx = 0
for i in 0 .. nbr.length - 1
a = nbr[i].to_i
if a == nil then return false end
idx = @table[idx][a]
end
print( "this number is " )
if idx == 0; print( "valid!" )
else print( "invalid!" )
end
puts
end
@table = Array.new(
[
[0,3,1,7,5,9,8,6,4,2], [7,0,9,2,1,5,4,8,6,3],
[4,2,0,6,8,7,1,3,5,9], [1,7,5,0,9,8,3,4,2,6],
[6,1,2,3,0,4,5,9,7,8], [3,6,7,4,2,0,9,5,8,1],
[5,8,6,9,7,2,0,1,3,4], [8,9,4,5,3,6,2,0,1,7],
[9,4,3,8,6,1,7,2,0,5], [2,5,8,1,4,3,6,7,9,0]
]
)
while true
print( "Number to check: " ) dammCheck( gets.chomp )
end</lang>
- Output:
Number to check: 5724this number is valid! Number to check: 5727 this number is invalid! Number to check: 112940 this number is invalid! Number to check: 112946 this number is valid! Number to check: 1321
this number is valid!
Rust
<lang rust>fn damm(number: &str) -> u8 {
static TABLE: [[u8; 10]; 10] = [
[0, 3, 1, 7, 5, 9, 8, 6, 4, 2],
[7, 0, 9, 2, 1, 5, 4, 8, 6, 3],
[4, 2, 0, 6, 8, 7, 1, 3, 5, 9],
[1, 7, 5, 0, 9, 8, 3, 4, 2, 6],
[6, 1, 2, 3, 0, 4, 5, 9, 7, 8],
[3, 6, 7, 4, 2, 0, 9, 5, 8, 1],
[5, 8, 6, 9, 7, 2, 0, 1, 3, 4],
[8, 9, 4, 5, 3, 6, 2, 0, 1, 7],
[9, 4, 3, 8, 6, 1, 7, 2, 0, 5],
[2, 5, 8, 1, 4, 3, 6, 7, 9, 0],
];
number.chars().fold(0, |row, digit| {
let digit = digit.to_digit(10).unwrap();
TABLE[row as usize][digit as usize]
})
}
fn damm_validate(number: &str) -> bool {
damm(number) == 0
}
fn main() {
let numbers = &["5724", "5727", "112946"];
for number in numbers {
let is_valid = damm_validate(number);
if is_valid {
println!("{:>6} is valid", number);
} else {
println!("{:>6} is invalid", number);
}
}
}</lang>
- Output:
5724 is valid 5727 is invalid 112946 is valid
Scala
Functional, (tail) recursive, concise and clean
<lang Scala>import scala.annotation.tailrec
object DammAlgorithm extends App {
private val numbers = Seq(5724, 5727, 112946, 112949)
@tailrec
private def damm(s: String, interim: Int): String = {
def table =
Vector(
Vector(0, 3, 1, 7, 5, 9, 8, 6, 4, 2),
Vector(7, 0, 9, 2, 1, 5, 4, 8, 6, 3),
Vector(4, 2, 0, 6, 8, 7, 1, 3, 5, 9),
Vector(1, 7, 5, 0, 9, 8, 3, 4, 2, 6),
Vector(6, 1, 2, 3, 0, 4, 5, 9, 7, 8),
Vector(3, 6, 7, 4, 2, 0, 9, 5, 8, 1),
Vector(5, 8, 6, 9, 7, 2, 0, 1, 3, 4),
Vector(8, 9, 4, 5, 3, 6, 2, 0, 1, 7),
Vector(9, 4, 3, 8, 6, 1, 7, 2, 0, 5),
Vector(2, 5, 8, 1, 4, 3, 6, 7, 9, 0)
)
if (s.isEmpty) if (interim == 0) "✔" else "✘" else damm(s.tail, table(interim)(s.head - '0')) }
for (number <- numbers) println(f"$number%6d is ${damm(number.toString, 0)}.")
}</lang>
- Output:
See it running in your browser by ScalaFiddle (JavaScript, non JVM) or by Scastie (remote JVM).
Sidef
<lang ruby>func damm(digits) {
static tbl = [
[0, 3, 1, 7, 5, 9, 8, 6, 4, 2],
[7, 0, 9, 2, 1, 5, 4, 8, 6, 3],
[4, 2, 0, 6, 8, 7, 1, 3, 5, 9],
[1, 7, 5, 0, 9, 8, 3, 4, 2, 6],
[6, 1, 2, 3, 0, 4, 5, 9, 7, 8],
[3, 6, 7, 4, 2, 0, 9, 5, 8, 1],
[5, 8, 6, 9, 7, 2, 0, 1, 3, 4],
[8, 9, 4, 5, 3, 6, 2, 0, 1, 7],
[9, 4, 3, 8, 6, 1, 7, 2, 0, 5],
[2, 5, 8, 1, 4, 3, 6, 7, 9, 0],
]
!digits.flip.reduce({|row,col| tbl[row][col] }, 0)
}
for n in [5724, 5727, 112946] {
say "#{n}:\tChecksum digit #{ damm(n.digits) ? : 'in'}correct."
}</lang>
- Output:
5724: Checksum digit correct. 5727: Checksum digit incorrect. 112946: Checksum digit correct.
uBasic/4tH
<lang>Push 0, 3, 1, 7, 5, 9, 8, 6, 4, 2: i = FUNC(_Data(0)) Push 7, 0, 9, 2, 1, 5, 4, 8, 6, 3: i = FUNC(_Data(i)) Push 4, 2, 0, 6, 8, 7, 1, 3, 5, 9: i = FUNC(_Data(i)) Push 1, 7, 5, 0, 9, 8, 3, 4, 2, 6: i = FUNC(_Data(i)) Push 6, 1, 2, 3, 0, 4, 5, 9, 7, 8: i = FUNC(_Data(i)) Push 3, 6, 7, 4, 2, 0, 9, 5, 8, 1: i = FUNC(_Data(i)) Push 5, 8, 6, 9, 7, 2, 0, 1, 3, 4: i = FUNC(_Data(i)) Push 8, 9, 4, 5, 3, 6, 2, 0, 1, 7: i = FUNC(_Data(i)) Push 9, 4, 3, 8, 6, 1, 7, 2, 0, 5: i = FUNC(_Data(i)) Push 2, 5, 8, 1, 4, 3, 6, 7, 9, 0: i = FUNC(_Data(i))
' Read the table
Push 112949, 112946, 5727, 5724 ' Put numbers on the stack
For i = 1 To Used() ' Read up to the number of stack items
Print Using "______"; Tos();" is "; ' Print the header If FUNC(_Damm (Str(Pop()))) Then Print "in"; Print "valid" ' invalid only if Damm() returns TRUE
Next ' Next stack item
End
_Data Param (1) ' Reads data in reverse order,
Local (2) ' starting with A@ c@ = a@ + Used() ' Calculate next offset
For b@ = c@-1 To a@ Step -1 ' Now place the elements @(b@) = Pop() ' that are retrieved from the stack Next b@ ' Next item
Return (c@) ' Return new offset
_Damm Param (1) ' Perform the Damm algorithm
Local (2)
c@ = 0 ' Reset the flag
For b@ = 0 To Len(a@) - 1 ' Check all characters in the string
c@ = @(c@*10 + peek(a@, b@) - ord("0"))
Next ' Next character
Return (c@) ' Return Flag</lang>
- Output:
5724 is valid 5727 is invalid 112946 is valid 112949 is invalid 0 OK, 0:984
Visual Basic .NET
<lang vbnet>Module Module1
ReadOnly table = {
{0, 3, 1, 7, 5, 9, 8, 6, 4, 2},
{7, 0, 9, 2, 1, 5, 4, 8, 6, 3},
{4, 2, 0, 6, 8, 7, 1, 3, 5, 9},
{1, 7, 5, 0, 9, 8, 3, 4, 2, 6},
{6, 1, 2, 3, 0, 4, 5, 9, 7, 8},
{3, 6, 7, 4, 2, 0, 9, 5, 8, 1},
{5, 8, 6, 9, 7, 2, 0, 1, 3, 4},
{8, 9, 4, 5, 3, 6, 2, 0, 1, 7},
{9, 4, 3, 8, 6, 1, 7, 2, 0, 5},
{2, 5, 8, 1, 4, 3, 6, 7, 9, 0}
}
Function Damm(s As String) As Boolean
Dim interim = 0
For Each c In s
interim = table(interim, AscW(c) - AscW("0"))
Next
Return interim = 0
End Function
Sub Main()
Dim numbers = {5724, 5727, 112946, 112949}
For Each number In numbers
Dim isvalid = Damm(number.ToString())
If isvalid Then
Console.WriteLine("{0,6} is valid", number)
Else
Console.WriteLine("{0,6} is invalid", number)
End If
Next
End Sub
End Module</lang>
- Output:
5724 is valid 5727 is invalid 112946 is valid 112949 is invalid
Wren
<lang ecmascript>import "/fmt" for Fmt
var table = [
[0, 3, 1, 7, 5, 9, 8, 6, 4, 2], [7, 0, 9, 2, 1, 5, 4, 8, 6, 3], [4, 2, 0, 6, 8, 7, 1, 3, 5, 9], [1, 7, 5, 0, 9, 8, 3, 4, 2, 6], [6, 1, 2, 3, 0, 4, 5, 9, 7, 8], [3, 6, 7, 4, 2, 0, 9, 5, 8, 1], [5, 8, 6, 9, 7, 2, 0, 1, 3, 4], [8, 9, 4, 5, 3, 6, 2, 0, 1, 7], [9, 4, 3, 8, 6, 1, 7, 2, 0, 5], [2, 5, 8, 1, 4, 3, 6, 7, 9, 0]
]
var damm = Fn.new { |input|
var interim = 0 for (c in input.bytes) interim = table[interim][c-48] return interim == 0
}
for (s in ["5724", "5727", "112946", "112949"]) {
System.print("%(Fmt.s(6, s)) %(damm.call(s))")
}</lang>
- Output:
5724 true 5727 false 112946 true 112949 false
zkl
<lang zkl>fcn damm(digits){ // digits is something that supports an iterator of integers
var [const] tbl=Data(0,Int, // 10x10 byte bucket
0, 3, 1, 7, 5, 9, 8, 6, 4, 2,
7, 0, 9, 2, 1, 5, 4, 8, 6, 3,
4, 2, 0, 6, 8, 7, 1, 3, 5, 9,
1, 7, 5, 0, 9, 8, 3, 4, 2, 6,
6, 1, 2, 3, 0, 4, 5, 9, 7, 8,
3, 6, 7, 4, 2, 0, 9, 5, 8, 1,
5, 8, 6, 9, 7, 2, 0, 1, 3, 4,
8, 9, 4, 5, 3, 6, 2, 0, 1, 7,
9, 4, 3, 8, 6, 1, 7, 2, 0, 5,
2, 5, 8, 1, 4, 3, 6, 7, 9, 0);
0 == digits.reduce(fcn(interim,digit){ tbl[interim*10 + digit] },0)
}</lang> <lang zkl>damm(List(5,7,2,4)).println(); // True damm(Data(0,Int,5,7,2,7).howza(0)).println(); // stream bytes, False damm((112946).split()).println(); // True</lang>
- Output:
True False True