Warning: session_start(): Cannot send session cookie - headers already sent by (output started at /index.php:4) in /index.php on line 8

Warning: session_start(): Cannot send session cache limiter - headers already sent (output started at /index.php:4) in /index.php on line 8

Fatal error: Uncaught Error: Call to undefined function mysql_connect() in /lib/class.Mysql.php:18 Stack trace: #0 /index.php(41): Mysql->Mysql() #1 {main} thrown in /lib/class.Mysql.php on line 18