java - How can I specify an array as a parameter -

i have following method:

public void testmethod() {     string id = card.people[4];     id = card.rooms[4];              } 

string id should either equal card.people[4] or card.rooms[4]. how can specify in parameter id should equal?

this general format use:

public void testmethod(mytype[] array) {     mytype fourthelement = array[4]; }