<?php
function gunler($basla, $bitir)
{
    $a = strtotime($basla);
    $b = strtotime($bitir);
    if($b > $a){
        while($a < $b){
            echo date('d-m-Y', $a).'<br>';
            $a += 86400;
        }
    }
}

gunler('2012-10-01', '2012-12-31');