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Re: Quicksort problem

by BrowserUk (Pope)
on Nov 22, 2011 at 05:49 UTC ( #939370=note: print w/ replies, xml ) Need Help??


in reply to Quicksort problem

If you add print "@_"; to the top of your sub, you'll see the problem.

Even when @less, @great and $pivot are empty, you still recurse.

Changing your first line to: my $pivot=pop // return; will allow the recursion to terminate.


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Re^2: Quicksort problem
by JediMasterT (Sexton) on Nov 22, 2011 at 13:49 UTC

    how does the // part work?

      JediMasterT,
      See perlop. The // operator essentially is a special or operator where it is testing the left hand side for definedness. I am pretty sure this became available in perl 5.10 four years ago but you can check perlhist and perldelta if you want to be sure.

      Cheers - L~R

      If the left part is not defined, the right is returned, otherwise the left one is. See perlop.

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