G'day code-ninja,

Use the defined function instead of attempting a numeric comparison. Here's some examples: 

$ perl -Mwarnings -le 'my $x; print 1 if $x == undef'
Use of uninitialized value in numeric eq (==) at -e line 1.
Use of uninitialized value $x in numeric eq (==) at -e line 1.
1

[download]
$ perl -Mwarnings -le 'my $x; print 1 if defined $x'

[download]
$ perl -Mwarnings -le 'my $x; print 1 if ! defined $x'
1

[download]

-- Ken

In reply to Re: Tree Data Structure by kcott
in thread Tree Data Structure by code-ninja

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