mysql_fetch_object and mysql_fetch_array in php

mysql_fetch_object returns the database as objects while mysql_fetch_array returns as an array. This will allow access to the data by the field names. 
example of mysql_fetch_object 

<?php
mysql_connect("hostname", "user", "password");
mysql_select_db("db");
$result = mysql_query("select * from content");
while ($res = mysql_fetch_object($result)) {
    echo $res->username;
    echo $res->place;
}
mysql_free_result($result);
?>

example of mysql_fetch_array

<?php
mysql_connect("hostname", "user", "password");
mysql_select_db("db");
$result = mysql_query("select * from content");
while ($res= mysql_fetch_array($result, MYSQL_ASSOC))

 {
 echo $res[0];
}
?>