Observe magic for the perl puzzle of the day, based on the math puzzle: 
#!/usr/bin/perl -w
use strict;
# my $a = 0; ## notice this is deleted!
$a += $_ for 1..1000; 
print "Answer: $a\n";

[download]
Points to ponder:
  1. Why does this even compile? It's use strict!
  2. Why no warnings? We're using undef in math!
  3. How come it still gets the same result? We didn't initialize the variable!
  4. Bonus question: can you tell why we removed all uses of $a as a casual variable from the third edition of Learning Perl?
Hmm. {grin}

-- Randal L. Schwartz, Perl hacker

In reply to •Perl Puzzle, was Re: (OT?) n(n-1)/2 by merlyn
in thread (OT?) n(n-1)/2 by mandog

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