1Algorithm::CheckDigits:U:sMeXrX_C0o0n2t(r3i)buted Perl DAolcguomreintthamt:i:oCnheckDigits::MXX_002(3)
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6 CheckDigits::MXX_002 - compute check digits for CAS
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9 use Algorithm::CheckDigits;
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11 $cas = CheckDigits('cas');
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13 if ($cas->is_valid('1333-74-0')) {
14 # do something
15 }
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17 $cn = $cas->complete('1333-74-');
18 # $cn = '1333-74-0'
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20 $cd = $cas->checkdigit('1333-74-0');
21 # $cd = '0'
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23 $bn = $cas->basenumber('1333-74-0');
24 # $bn = '1333-74-'
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27 ALGORITHM
28 1. Beginning right with the second digit all digits are weighted
29 ascending starting with 1.
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31 2. The sum of those products is computed.
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33 3. The checksum is the last digit of the sum from step 2 (modulo 10).
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35 METHODS
36 is_valid($number)
37 Returns true only if $number consists solely of numbers and the
38 last digit is a valid check digit according to the algorithm given
39 above.
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41 Returns false otherwise,
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43 complete($number)
44 The check digit for $number is computed and concatenated to the end
45 of $number.
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47 Returns the complete number with check digit or '' if $number does
48 not consist solely of digits and spaces.
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50 basenumber($number)
51 Returns the basenumber of $number if $number has a valid check
52 digit.
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54 Return '' otherwise.
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56 checkdigit($number)
57 Returns the checkdigit of $number if $number has a valid check
58 digit.
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60 Return '' otherwise.
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62 EXPORT
63 None by default.
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66 Mathias Weidner, "<mamawe@cpan.org>"
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69 Aaron W. West pointed me to a fault in the computing of the check
70 digit.
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72 HERMIER Christophe made me aware that CAS is now assigning 10-digit CAS
73 Registry Numbers (http://www.cas.org/newsevents/10digitrn.html)
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76 perl, CheckDigits, www.pruefziffernberechnung.de, www.cas.org
77 http://www.cas.org/expertise/cascontent/registry/checkdig.html
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81perl v5.32.0 2020-07-28Algorithm::CheckDigits::MXX_002(3)