NAME

CheckDigits::M11_009 - compute check digits NRIC (SG)

SYNOPSIS

  use Algorithm::CheckDigits;

  $nric = CheckDigits('nric_sg');

  if ($nric->is_valid('S1234567D')) {
	# do something
  }

  $cn = $nric->complete('S1234567');
  # $cn = 'S1234567D'

  $cd = $nric->checkdigit('S1234567D');
  # $cd = 'D'

  $bn = $nric->basenumber('S1234567D');
  # $bn = 'S1234567';
  

DESCRIPTION

ALGORITHM

1. Beginning left every digit is weighted with 2, 7, 6, 5, 4, 3, 2

2. The weighted digits are added.

3. The sum from step 2 is taken modulo 11.

4. The checkdigit is 11 minus the sum from step 3 converted to a character according to the following table:

   @cd = ('','A','B','C','D','E','F','G','H','I','Z','J', );

METHODS

is_valid($number)

Returns true only if $number consists of seven digits (optional preceded by a letter out of 'F', 'G', 'S', 'T') followed by a valid letter according to the algorithm given above.

Returns false otherwise,

complete($number)

The check letter for $number is computed and appended to the end of $number.

Returns the complete number with check digit or '' if $number does not consist solely of digits and letters.

basenumber($number)

Returns the basenumber of $number if $number has a valid check digit.

Return '' otherwise.

checkdigit($number)

Returns '' if $number is valid.

Return undef otherwise.

EXPORT

None by default.

AUTHOR

Mathias Weidner, <mathias@weidner.in-bad-schmiedeberg.de>

SEE ALSO

perl, CheckDigits, www.pruefziffernberechnung.de,