It should be
echo $dateClass->getDay();
getDay is a method OR easier known as a function you wouldnt try a function as
function quicktest()
{
return 1;
}
echo quicktest;
Also just looking over this wouldn't this be better way to do it.
class dateClass
{
var $timestamp;
function dateClass()
{
$this->timestamp = time();
}
function setTimestamp( $time )
{
$this->timestamp = $time;
}
function getDay()
{
return date( "j", $this->timestamp );
}
}
$date = new dateClass();
echo $date->getDay();
The other thing i noticed which is fixed in the above is your setting timestamp as a date when the second parameter of date must be int which mktime & time do not date as it returns string.