Studente 1: :
Studente 2: Array:
Studente 3: Array:
Array
(
    [nome] => bob
    [cognome] => rossi
    [eta] => 12
    [media] => 4.5
)
Array
(
    [0] => Mario
    [1] => rossi
    [2] => 18
    [3] => 5
)
Array
(
    [nome] => bob
    [cognome] => rossi
    [eta] => 12
    [media] => 4.5
)