重载运算符<<不起作用

Im在使用重载运算符输出Card对象的数据成员时遇到问题<lt；

我收到一个错误，上面写着

"JS:：运算符<<（std:：__1:：basic_stream>&，JS:：Card const&）"，引用自：链接器命令失败，退出代码为1（使用-v查看调用）

//
//主要.cpp

#include "Card.h"
#include "Deck.h"
#include <iostream>
using std::cout;
using namespace JasonSteindorf;
int main(int argc, const char * argv[]) {
    //Deck d;
    //d.shuffle();
    Card c(5,3);  //5 of Clubs
    Card c2;      //Ace of Diamonds
    cout << c;         //not working ????????  should says 5 of Clubs
    c.displayCard();   //works
    return 0;
}

//
//甲板.h

#ifndef JS_DECK_H
#define JS_DECK_H
#include <iostream>
using std::cout;
#include <vector>
using std::vector;
namespace JS {
    //forward declaration
    class Card;
    class Deck {
    public:
        Deck();
        void shuffle();
    private:
        vector<Card>cards;
    };
}
#endif

//
//Deck.cpp

#include "Deck.h"
#include "Card.h"
#include <algorithm>
using std::random_shuffle;
#include <iostream>
using std::cout;
using namespace JS;
Deck::Deck() {
    cout << "A DECK OF CARDS!!!nn";
    for(int suit = 0; suit < 4; suit++) {
        for(int rank = 1; rank < 14; rank++) {
            cards.push_back(Card(rank, suit));
        }
        cout << 'n';
    }
}
void
Deck::shuffle() {
    random_shuffle(cards.begin(), cards.end());
    //for(int s = 0; s < 52; s++)
      //  cards.at(s)->displayCard();
    for(vector<Card>::iterator it = cards.begin(); it < cards.end(); it++) {
        Card a = *it;
        a.displayCard();
    }
}

//
//卡片.h

#ifndef JS_CARD_H
#define JS_CARD_H
#include <iostream>
using std::ostream;
#include <string>
using std::string;
#include <vector>
using std::vector;
namespace JS {
    class Card {
    public:
        enum Suit { DIAMONDS, HEARTS, SPADES, CLUBS };
        enum Rank { ACE = 1, JACK = 11, QUEEN = 12, KING = 13 };
        Card();
        Card(int rank, int suit);
        string getRank() const;
        string getSuit() const;
        int getRankValue() const;
        int operator+(const Card& rhs);
        void displayCard() const;
    private:
        int rank;
        int suit;
    };
    //ostream &operator<<(ostream &out, const Card &rhs);
    ostream& operator << (ostream& out, const Card& c);
}
#endif

//
//Card.cpp

#include "Card.h"
#include <iomanip>
using std::setw;
using std::right;
#include <iostream>
using std::cout;
#include <sstream>
using std::stringstream;
using namespace JS;
Card::Card(): rank(1), suit(0){
    displayCard();
}
Card::Card(int rank, int suit) : rank(rank), suit(suit) {
    displayCard();
}
string
Card::getSuit() const {
    switch (suit) {
        case SPADES:   return "Spades";   break;
        case HEARTS:   return "Hearts";   break;
        case DIAMONDS: return "Diamonds"; break;
        case CLUBS:    return "Clubs";    break;
        default:       return "";         break;
    }
}
string
Card::getRank() const {
    switch (rank) {
        case ACE:   return "Ace";   break;
        case JACK:  return "Jack";  break;
        case QUEEN: return "Queen"; break;
        case KING:  return "King";  break;
        default:
            stringstream out;
            out << rank;
            return out.str();
            break;
    }
}
int
Card::getRankValue() const {
    switch (rank) {
        case ACE:   return 1;    break;
        case JACK:
        case QUEEN:
        case KING:  return 10;   break;
        default:    return rank; break;
    }
}
int
Card::operator+(const Card& rhs) {
    return (getRankValue() + rhs.getRankValue());
}
ostream& operator <<(ostream& out, const Card& c)
{
    out << c.getRank() << " of " << c.getSuit();
    return out;
}
/*ostream
&operator<<(ostream &out, const Card &rhs) {
    out << rhs.getRank() << " of " << rhs.getSuit();
    return out;
}*/

void
Card::displayCard() const {
    cout << right << setw(5)   << getRank()
                  << setw(3)   << " of "
                  << getSuit() << 'n';
}