#!/usr/bin/perl -w
use strict;

## The ||= operator tests for "truthfulness"
## The //= operator tests for "definedness"


my $z = 25;
my $x = 550;
$z ||= $x;
print "$z\n";  #prints 25 because z is already true

my $y;  # $y is undefined
print "y is not defined\n" if !defined $y;
$y //= 32;
print "y is is defined now as $y\n" if defined $y;

my $k;  #$k is undefined
        #An undefined value evaluates to "false"
        #and the assignment proceeds
        
$k ||= 3842;
print "k is $k ...hey I'm defined now!\n";


__END__
25
y is not defined
y is is defined now as 32
k is 3842 ...hey I'm defined now!