But now say if third value that is generated is 80 . At this point in time $root still points to the orignal tree with value 40. Now because $root is already defined it skips to the if else condition , and makes a call that 80 > 40 , hence it should be inserted to the right But $tree->{Right} is already defined , and it contains the value 60, so it never executes the actual routine to create a reference to a new tree

($q=q:Sq=~/;[c](.)(.)/;chr(-||-|5+lengthSq)`"S|oS2"`map{chr |+ord
}map{substrSq`S_+|`|}3E|-|`7**2-3:)=~y+S|`+$1,++print+eval$q,q,a,
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( I understand till here) But now say if third value that is generated is 80 . At this point in time $root still points to the orignal tree with value 40. Now because $root is already defined it skips to the if else condition , and makes a call that 80 > 40 , hence it should be inserted to the right But $tree->{Right} is already defined , and it contains the value 60, so it never executes the actual routine to create a reference to a new tree .....

- and makes a call that 80 > 40 , hence it should be inserted to the right

Yes. So it calls the insert function on the right tree. When entering this new function call, it finds a node where the value is 60. It compares the values, and since 80 is larger than 60, it sees that it should call the insert function recursively once more on the right side. When it gets to this next level, the node below 60 does not exists yet, so that insert can actually create the node 80 below (and right of) node 60.

Update ( Dec 06, 2015 at 22:25 UTC):

This graph may make it clearer:

          40
         /  \
        /    \
             60
            /  \
                \
                80
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          40
         /  \
        /    \
             60
            /  \
           /    \
          50    80
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And, since you appear not to have seen my earlier warning, let me repeat that the link you're giving on the O'Reilly books is on a site (presumably in Ukraine) which most probably does not have the right to publish these contents on the Internet.

Thanks for the response. I see that the link has been removed. Going forward I will keep this in mind.

Hello ,
How can I do a Breadth First search for a binary tree in perl ?
For the above code how can I go ahead and create a subroutine for Breadth First search ?
For a breadth first search , since I have to visit the left node first and then the right node and then repeat this process till I reach the very end , I fee its sort of tricky...
I have written a snippet below for "Depth First" search , but not able to think for a Breadth first search


sub depthFirst {

my ($tree) =@_;
return unless ($tree);

print $tree->{Value};
depthFirst($tree->{Left});
depthFirst($tree->{Right});

}
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