Beefy Boxes and Bandwidth Generously Provided by pair Networks
P is for Practical
 
PerlMonks  

Comment on

( #3333=superdoc: print w/ replies, xml ) Need Help??
I'm trying to make a binary tree object which uses a recursively called new() method to create a tree n nodes deep. The problem is that whenever i try to assign new nodes to the object branch variables from within the object methods it doesn't work, but whenever I assign a node to a branch outside of the object method functions, it works perfectly.

That's probably a bad explanation of the problem, but hopefully my code is self explanatory. For those of you who are going to point me to modules which implement a binary tree, I'm doing this as an excercise in preparation for a larger project involving complex objects and data structures, etc. Thanks for your help, this one's driving me mad.
package bin_tree; #create a new instance of the bin_tree object, taking #$depth as an ar +gument... Create a binary tree, #recursively calling new() in order to create a node with #the desired + depth. sub new{ $class=shift; $depth=shift; #pull the class values and the depth beneath the nod +e desired, 0 for no lower nodes $self={value,a,b}; #make our object as an anonymous hash with keyw +ords but no values yet, that way the a and b keys (our branches) defa +ult evaluate to null $self->{value}=0; print $self->{value},"\n"; #just a debugging statement to try to f +igure out whats going on while ($depth >= 1){ #if we need to get deep, recursively call the + new() method, assigning the created objects to our a and b branches $depth--; $self->{a} = bin_tree->new($depth); #problem is here... the ne +w binary tree node never gets returned $self->{b} = bin_tree->new($depth); print $self->{a},"\n"; #debugging statement, this still evalua +tes to null, even though it should be set as an object reference now } bless $self, $class; #make object return $self; #return object } #5 minute depth test function, recursively runs down the "a" side of a + binary tree, returns the depth eventually sub depth_test{ $self=shift; print $i++,"\n"; if (defined $self->{a}){ $depth=$self->{a}->depth_test(); } return $depth+1; } #try to create a three node deep binary tree $bintree = bin_tree->new(3); print "Before:",$bintree->{a},"\n"; $deep = $bintree->depth_test(); print "Depth:",$deep,"\n"; #prove that new() call is just creating the + first level node) $bintree->{a} = bin_tree->new(); $bintree->{a}->{a} = bin_tree->new(); print "After:",$bintree->{a},"\n"; $deep = $bintree->depth_test(); print "Depth:",$deep,"\n"; #prove that when the code is outside of the + object methods, i can use my technique to build a tree

In reply to recursive creation of attached objects? by Anonymous Monk

Title:
Use:  <p> text here (a paragraph) </p>
and:  <code> code here </code>
to format your post; it's "PerlMonks-approved HTML":



  • Posts are HTML formatted. Put <p> </p> tags around your paragraphs. Put <code> </code> tags around your code and data!
  • Read Where should I post X? if you're not absolutely sure you're posting in the right place.
  • Please read these before you post! —
  • Posts may use any of the Perl Monks Approved HTML tags:
    a, abbr, b, big, blockquote, br, caption, center, col, colgroup, dd, del, div, dl, dt, em, font, h1, h2, h3, h4, h5, h6, hr, i, ins, li, ol, p, pre, readmore, small, span, spoiler, strike, strong, sub, sup, table, tbody, td, tfoot, th, thead, tr, tt, u, ul, wbr
  • You may need to use entities for some characters, as follows. (Exception: Within code tags, you can put the characters literally.)
            For:     Use:
    & &amp;
    < &lt;
    > &gt;
    [ &#91;
    ] &#93;
  • Link using PerlMonks shortcuts! What shortcuts can I use for linking?
  • See Writeup Formatting Tips and other pages linked from there for more info.
  • Log In?
    Username:
    Password:

    What's my password?
    Create A New User
    Chatterbox?
    and the web crawler heard nothing...

    How do I use this? | Other CB clients
    Other Users?
    Others exploiting the Monastery: (12)
    As of 2015-07-29 18:52 GMT
    Sections?
    Information?
    Find Nodes?
    Leftovers?
      Voting Booth?

      The top three priorities of my open tasks are (in descending order of likelihood to be worked on) ...









      Results (267 votes), past polls