Listing 3: Template class <priority_queue>

  // TEMPLATE CLASS priority_queue
template<class Ty, class C = vector<Ty>,
 class Pr = less<C::value_type> >
 class priority_queue {
public:
 typedef C container_type;
 typedef typename C::value_type value_type;
 typedef typename C::size_type size_type;
 explicit priority_queue()
  : c(), comp() {}
 explicit priority_queue(const Pr& X)
  : c(), comp(X) {}
 explicit priority_queue(const Pr& X, const C& Cont)
  : c(Cont), comp(X)
  {make_heap(c.begin(), c.end(), comp); }
 template<class It>
  priority_queue(It F, _It L)
  : c(F, L), comp()
  {make_heap(c.begin(), c.end(), comp); }
 template<class It>
  priority_queue(It F, It L, const Pr& X)
  : c(F, L), comp(X)
  {make_heap(c.begin(), c.end(), comp); }
 template<class It>
  priority_queue(It F, It L, const Pr& X,
   const C& Cont)
  : c(Cont), comp(X)
  {c.insert(c.end(), F, L);
  make_heap(c.begin(), c.end(), comp); }
 bool empty() const
  {return (c.empty()); }
 size_type size() const
  {return (c.size()); }
 value_type& top()
  {return (c.front()); }
 const value_type& top() const
  {return (c.front()); }
 void push(const value_type& X)
  {c.push_back(X);
  push_heap(c.begin(), c.end(), comp); }
 void pop()
  {pop_heap(c.begin(), c.end(), comp);
  c.pop_back(); }
protected:
 C c;
 Pr comp;
 };
/* End of File */