to add to John's answer:
what you want to pass to the shuffle function is a deck of cards from the class deckOfCards that you've declared in main; however, the deck of cards or vector<Card> deck that you've declared in your class is private, so not accessible from outside the class. this means you'd want a getter function, something like this:
class deckOfCards
{
private:
vector<Card> deck;
public:
deckOfCards();
static int count;
static int next;
void shuffle(vector<Card>& deck);
Card dealCard();
bool moreCards();
vector<Card>& getDeck() { //GETTER
return deck;
}
};
this will in turn allow you to call your shuffle function from main like this:
deckOfCards cardDeck; // create DeckOfCards object
cardDeck.shuffle(cardDeck.getDeck()); // shuffle the cards in the deck
however, you have more problems, specifically when calling cout. first, you're calling the dealCard function wrongly; as dealCard is a memeber function of a class, you should be calling it like this cardDeck.dealCard(); instead of this dealCard(cardDeck);.
now, we come to your second problem - print to standard output. you're trying to print your deal card, which is an object of type Card by using the following instruction:
cout << cardDeck.dealCard();// deal the cards in the deck
yet, the cout doesn't know how to print it, as it's not a standard type. this means you should overload your << operator to print whatever you want it to print when calling with a Card type.