c++ - overloading operator<< not working -

im having trouble outputting data members of card object using overloaded operator<<

i'm getting error says

"js::operator<<(std::__1::basic_ostream >&, js::card const&)", referenced from: linker command failed exit code 1 (use -v see invocation)

//
//main.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; } 

//
//deck.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!!!\n\n";      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 = cards.begin(); < cards.end(); it++) {         card = *it;         a.displaycard();     }  } 

//
//card.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'; } 

card.h declares operator in namespace:

namespace js {     ostream& operator << (ostream& out, const card& c); } 

but card.cpp defines different operator in global namespace:

ostream& operator <<(ostream& out, const card& c) {...} 

your choices are:

• put declaration in global namespace; or
• put definition in js namespace; or
• qualify name js::operator<< in definition.