template<> struct char_traits<wchar_t> { typedef wchar_t char_type; typedef wint_t int_type; typedef streamoff off_type; typedef wstreampos pos_type; typedef mbstate_t state_type; static void assign(char_type& c1, const char_type& c2); static bool eq(const char_type& c1, const char_type& c2); static bool lt(const char_type& c1, const char_type& c2); static int compare(const char_type* s1, const char_type* s2, size_t n); static size_t length(const char_type* s); static const char_type* find(const char_type* s, size_t n, const char_type& a); static char_type* move(char_type* s1, const char_type* s2, size_t n); static char_type* copy(char_type* s1, const char_type* s2, size_t n); static char_type* assign(char_type* s, size_t n, char_type a); static int_type not_eof(const int_type& c); static char_type to_char_type(const int_type& c); static int_type to_int_type(const char_type& c); static bool eq_int_type(const int_type& c1, const int_type& c2); static int_type eof(); };
//: C05:BearCorner2.cpp // Illustrates policy classes. #include <iostream> #include "BearCorner.h" using namespace std; // Policy classes (require a static doAction() function): class Feed { public: static const char* doAction() { return "Feeding"; } }; class Stuff { public: static const char* doAction() { return "Stuffing"; } }; // The Guest template (uses a policy and a traits class) template<class Guest, class Action, class traits = GuestTraits<Guest> > class BearCorner { Guest theGuest; typedef typename traits::beverage_type beverage_type; typedef typename traits::snack_type snack_type; beverage_type bev; snack_type snack; public: BearCorner(const Guest& g) : theGuest(g) {} void entertain() { cout << Action::doAction() << " " << theGuest << " with " << bev << " and " << snack << endl; } }; int main() { Boy cr; BearCorner<Boy, Feed> pc1(cr); pc1.entertain(); Bear pb; BearCorner<Bear, Stuff> pc2(pb); pc2.entertain(); } ///:~
Listado 6.42. C05/BearCorner2.cpp