printf％.4f for IP？

I would like to print an IP in fixed way.. example

12.12.1.0

would tured to

012.012.001.000

what's the best method do it ?

printf("%.4f.%.4f.%.4f.%.4f",$ip); ?

With zero padding:

$ip = "12.12.1.0";

vprintf("%03d.%03d.%03d.%03d", explode('.', $ip));