use warnings;
use List::Util qw(uniq uniqnum);

$x = sqrt 2.0;

# Create $y with a less precise
# approximation of sqrt 2

$y = "$x" + 0;

#$y != $x

print "unequivalent\n" if $x != $y;

# But $x and $y both stringify
# to 1.4142135623731, hence:

$count = uniq($x, $y);
print $count;

__END__

# Outputs:
unequivalent
1