Damm algorithm

From Rosetta Code
Damm algorithm is a draft programming task. It is not yet considered ready to be promoted as a complete task, for reasons that should be found in its talk page.

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.



ALGOL 68[edit]

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
Output:
check digit of 5724 is valid
check digit of 5727 is invalid
check digit of 112946 is valid

AWK[edit]

# 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"
}
Output:
T 5724
F 5727
T 112946

C[edit]

This example does not show the output mentioned in the task description on this page (or a page linked to from here). Please ensure that it meets all task requirements and remove this message.
Note that phrases in task descriptions such as "print and display" and "print and show" for example, indicate that (reasonable length) output be a part of a language's solution.


#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;
}

C#[edit]

Translation of: Java
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);
}
}
}
}
}
Output:
  5724 is valid
  5727 is invalid
112946 is valid
112949 is invalid

Clojure[edit]

(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)))))
Output:
=> (damm? "5724")
true
=> (damm? "5727")
false
=> (damm? "112946")
true

D[edit]

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");
}
}
}
Output:
  5724 is valid
  5727 is invalid
112946 is valid
112949 is invalid

Fortran[edit]

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.
      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

Output:

 T 5724
 F 5727
 T 112946

FreeBASIC[edit]

' 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
Output:
Checksum test: 5724 is valid
Checksum test: 5727 is invalid
Checksum test: 112946 is valid

Go[edit]

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))
}
}
Output:
  5724  true
  5727  false
112946  true
112949  false

J[edit]

Solution:

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

Example Usage:

   checkDamm&> 5724 5727 112946
1 0 1

Java[edit]

Translation of: Kotlin
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);
}
}
}
}
Output:
  5724 is valid
  5727 is invalid
112946 is valid
112949 is invalid

Julia[edit]

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Note that phrases in task descriptions such as "print and display" and "print and show" for example, indicate that (reasonable length) output be a part of a language's solution.


Works with: Julia version 0.6
Translation of: Python
function checkdigit(input::AbstractString)
all(isnumber, input) || throw(ArgumentError("input must be all digits"))
 
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 input
row = matrix[row + 1][d - '0' + 1]
end
return row
end

Kotlin[edit]

// 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"}")
}
}
Output:
  5724 is valid
  5727 is invalid
112946 is valid
112949 is invalid

Lua[edit]

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
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[edit]

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Note that phrases in task descriptions such as "print and display" and "print and show" for example, indicate that (reasonable length) output be a part of a language's solution.


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.

Perl 6[edit]

Works with: Rakudo version 2017.05
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."
}
Output:
5724:	Checksum digit correct.
5727:	Checksum digit incorrect.
112946:	Checksum digit correct.

Python[edit]

This example does not show the output mentioned in the task description on this page (or a page linked to from here). Please ensure that it meets all task requirements and remove this message.
Note that phrases in task descriptions such as "print and display" and "print and show" for example, indicate that (reasonable length) output be a part of a language's solution.


#!/usr/bin/env python2
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)
)
input = raw_input()
def checkdigit(input):
row = 0
for eachdigit in input:
row = matrix[row][int(eachdigit)]
return row
output = checkdigit(input)
print str(input)+str(output)

Racket[edit]

#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)))

No output from checks means that all tests passed.

REXX[edit]

manufactured table[edit]

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
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[edit]

/*REXX pgm uses H. Michael Damm's algorithm to validate numbers with suffixed check dig.*/
@.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 algorithme for some #'s*/
exit /*stick a fork in it, we're all done. */
/*──────────────────────────────────────────────────────────────────────────────────────*/
Damm: arg z; do j=1 for words(z); x=word(z, j); L=length(x)
$=0; VCD= 'valid check digit'
do p=1 for L; g=$; $=substr(@.$, 1 + substr(x, p, 1), 1)
end /*p*/
if $==0 then say ' ' VCD right(x,1) " for " x
else say 'in'VCD right(x,1) " for " x ' (should be' g")"
end /*j*/
return
output   when using the (internal) default inputs:
  valid check digit 4  for  5724
invalid check digit 7  for  5727   (should be 4)
  valid check digit 6  for  112946
invalid check digit 0  for  112940   (should be 6)

Ring[edit]

# 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

Output:

5724 is valid
5727 is invalid
112946 is valid

Ruby[edit]

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
Output:
Number to check: 5724

this 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!

Scala[edit]

Functional, (tail) recursive, concise and clean[edit]

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)}.")
 
}
Output:
See it running in your browser by ScalaFiddle (JavaScript, non JVM) or by Scastie (remote JVM).

Sidef[edit]

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.reduce({|row,col| tbl[row][col] }, 0)
}
 
for n in [5724, 5727, 112946] {
say "#{n}:\tChecksum digit #{ damm(n.digits) ? '' : 'in'}correct."
}
Output:
5724:	Checksum digit correct.
5727:	Checksum digit incorrect.
112946:	Checksum digit correct.

zkl[edit]

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)
}
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
Output:
True
False
True