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  1. use strict;
  2. use warnings;
  3.  
  4. sub is_valid_isbn {
  5. 	my @digits = split //, shift;
  6.  
  7. 	(@digits == 13) or return;
  8.  
  9. 	my $n = 0;
  10. 	foreach(0..12){
  11. 		$n += $digits[$_] * ($_ % 2 ? 3 : 1);
  12. 	}
  13.  
  14. 	return ($n % 10 == 0);
  15. }
  16.  
  17. foreach(qw( 9784062772211 9784150315684 )){
  18. 	printf("%s => %s\n", $_, (is_valid_isbn($_) ? "OK" : "NG"));
  19. }
  20.  
Success #stdin #stdout 0s 4684KB
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stdin
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Standard input is empty
stdout
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9784062772211 => OK
9784150315684 => NG
https://ideone.com/zQASi
language:
Perl (perl 5.28.1)
created:
11 years ago
visibility:
public

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