On Jul 25, Connie Chan said: >In normal case, when we want to swap 2 var, >, say $x and $y, we do in this way : > >$z = $x; $x = $y; $y = $z; # Swapped
Perl allows you to do ($x, $y) = ($y, $x); >$x ^= $y ; $y ^= $x ; $x ^= $y; # Swapped > >It works !! but how that works ? Because of the way XOR works. A XOR (A XOR B) = B Here's a less tricky example: $x = 10; $y = 13; $x = $x + $y; # 10 + 13 = 23 $y = $x - $y; # 23 - 13 = 10 $x = $x - $y; # 23 - 10 = 13 And then with XOR: $x = 10; # 1010 $y = 13; # 1101 $x = $x ^ $y; # 1010 ^ 1101 = 0111 $y = $x ^ $y; # 1101 ^ 0111 = 1010 $x = $x ^ $y; # 0111 ^ 1010 = 1101 -- Jeff "japhy" Pinyan [EMAIL PROTECTED] http://www.pobox.com/~japhy/ RPI Acacia brother #734 http://www.perlmonks.org/ http://www.cpan.org/ ** Look for "Regular Expressions in Perl" published by Manning, in 2002 ** <stu> what does y/// stand for? <tenderpuss> why, yansliterate of course. [ I'm looking for programming work. If you like my work, let me know. ] -- To unsubscribe, e-mail: [EMAIL PROTECTED] For additional commands, e-mail: [EMAIL PROTECTED]
