Damm algorithm: Difference between revisions
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Function Damm(digit_str As String) As UInteger |
Function Damm(digit_str As String) As UInteger |
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Dim As UInteger table(10,10) => { { 0, 3, 1, 7, 5, 9, 8, 6, 4, 2 } , _ |
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{ 7, 0, 9, 2, 1, 5, 4, 8, 6, 3 } , { 4, 2, 0, 6, 8, 7, 1, 3, 5, 9 } , _ |
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{ 1, 7, 5, 0, 9, 8, 3, 4, 2, 6 } , { 6, 1, 2, 3, 0, 4, 5, 9, 7, 8 } , _ |
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{ 3, 6, 7, 4, 2, 0, 9, 5, 8, 1 } , { 5, 8, 6, 9, 7, 2, 0, 1, 3, 4 } , _ |
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{ 8, 9, 4, 5, 3, 6, 2, 0, 1, 7 } , { 9, 4, 3, 8, 6, 1, 7, 2, 0, 5 } , _ |
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{ 2, 5, 8, 1, 4, 3, 6, 7, 9, 0 } } |
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Dim As UInteger i, col_i, old_row_i, new_row_i |
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For i = 0 To Len(digit_str) -1 |
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col_i = digit_str[i] - Asc("0") |
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new_row_i = table(old_row_i, col_i) |
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old_row_i = new_row_i |
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Next |
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Return new_row_i |
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End Function |
End Function |
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Do |
Do |
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Read test_string |
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If test_string = "" Then Exit Do |
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Print "Checksum test: ";test_string; |
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checksum = Damm(test_string) |
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If checksum = 0 Then |
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Print " is valid" |
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Else |
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Print " is invalid" |
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End If |
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Loop |
Loop |
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Revision as of 19:59, 10 July 2018
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
<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>
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
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
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
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(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</lang>
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>
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.
Python
<lang Python>#!/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)</lang>
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.
REXX
manufactured table
<lang 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
<lang rexx>/*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</lang>
- 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
<lang ring># Project : Damm algorithm
- Date : 2017/11/05
- Author : Gal Zsolt [~ CalmoSoft ~]
- Email : <calmosoft@gmail.com>
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!
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.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.
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