#!/usr/local/bin/perl
$result = $undefined + 2;   # $undefined is not defined
$sir= $undefined + "2";

print ("The value of \$result is $result.\n");
print ("The value of \$sir is $sir.\n");
$undefined='n';
print ("The value of \$sir is $sir.\n");

print ('press ENTER to EXIT');
$in = <STDIN>;