- print_r: documentation ( source)
- sprintf: documentation ( source)
<?php
$dataoD = new DateTime("2015-01-10");
$dataDo = new DateTime("2015-03-24");
$roznica= $dataDo->diff($dataoD);
echo sprintf("Minęło %s dni.", $roznica->days) . PHP_EOL;
print_r($roznica);