printf("%.16e\n", $dollar1);
printf("%.16e\n", $dollar2);

##</code><code>##

>perl -le"printf '%.16e', 0.1"
1.0000000000000001e-001
                 ^
                 |

##</code><code>##

if (sprintf('%.2f', $dollar1) ne sprintf('%.2f', $dollar2)) {
  print "$dollar1 != $dollar2\n";
}

##</code><code>##

if ($cents1 != $cents2)) {
  print $cents1/100, ' != ', $cents2/100, "\n";
}