#!perl
use strict;
use warnings;
use Carp;
my $x = -4;
print "Hi!\nAbout to get square_root($x)\n";
warn "\$x is -4";
my $result = square_root($x);
print "$result\n";
sub square_root {
my $arg = shift;
carp "debug: In square_root, $arg is $arg";
if ($arg < 0) {
croak "square_root of negative number: $arg";
}
return sqrt($arg);
}