Re: Boolean counter?

Two more approaches:

- Using hashes:

  my %Next = ( 0 => 1, 1 => 0);
  my $Counter = 0;
  #...
  $Counter = $Next{$Counter};
[download]

- Decreasing instead of increasing:

  $Counter = abs --$Counter;
[download]

Comment on Re: Boolean counter? Select or Download Code
Re^2: Boolean counter? by shawnhcorey (Pilgrim) on Dec 07, 2009 at 14:07 UTC
`$Counter = - --$Counter;`	[reply] [d/l]
Re^3: Boolean counter? by JavaFan (Canon) on Dec 07, 2009 at 15:13 UTC
The behaviour of that is actually not defined. You may end up with $Counter being -1, or with purple daemons coming out of your USB port, ready to chew off your fingers.	[reply]
Re^4: Boolean counter? by ikegami (Pope) on Dec 07, 2009 at 16:09 UTC
What about it is not defined?	[reply]
Re^5: Boolean counter? by ikegami (Pope) on Dec 07, 2009 at 16:57 UTC
Re^6: Boolean counter? by JavaFan (Canon) on Dec 07, 2009 at 21:55 UTC
Some notes below your chosen depth have not been shown here
Re^4: Boolean counter? by Anonymous Monk on Dec 07, 2009 at 16:15 UTC
$i appears only once, the behaviour is defined `$ perl -MO=Deparse,-p -le"print - --$i" BEGIN { $/ = "\n"; $\ = "\n"; } print((-(--$i))); -e syntax OK` [download] You were thinking of `print(-( ++$i - --$i ))` [download]	[reply] [d/l] [select]
Re^5: Boolean counter? by ikegami (Pope) on Dec 07, 2009 at 17:01 UTC
Re^3: Boolean counter? by ikegami (Pope) on Dec 07, 2009 at 17:08 UTC
Don't modify a variable that you're using elsewhere in an expression. At best, it's unclear. At worse, the result is undefined. `$toggle = - --$toggle;` [download] should be `$toggle = -( $toggle - 1 );` [download] which can be shortened to previously mentioned `$toggle = 1 - $toggle;` [download]	[reply] [d/l] [select]


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