Actually, the value of $sum after my $sum is undefined.

The following program demonstrates that unless a scalar is set to a value it is initially undefined: 

use strict;
my $sum;
unless (defined($sum)) {
    print '$sum is undefined', "\n";
} else {
    print 'The value of $sum is ', "$sum\n";
}

[download]
This program returns the message that $sum is undefined.

In reply to Re: (jcwren) Re: Still confused by sierrathedog04
in thread Still confused by yabba

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