STL堆栈和priority_queue的插入器

Question

std::vector , std::list and std::deque have std::back_inserter , and std::set has std::inserter .

For std::stack and std::priority_queue I would assume the equivalent inserter would be a push() but I can't seem to find the correct function to call.

My intent is to be able to use the following function with the correct insert iterator:

#include <string>
#include <queue>
#include <iterator>

template<typename outiter>
void foo(outiter oitr)
{
   static const std::string s1 ("abcdefghji");
   static const std::string s2 ("1234567890");
   *oitr++ = s1;
   *oitr++ = s2;
}

int main()
{
   std::priority_queue<std::string> spq;
   std::stack<std::string> stk;

   foo(std::inserter(spq));
   foo(std::inserter(stk));

   return 0;
}

Answer 1

You can always go your own way and implement an iterator yourself. I haven't verified this code but it should work. Emphasis on "I haven't verified."

template <class Container>
  class push_insert_iterator:
    public iterator<output_iterator_tag,void,void,void,void>
{
protected:
  Container* container;

public:
  typedef Container container_type;
  explicit push_insert_iterator(Container& x) : container(&x) {}
  push_insert_iterator<Container>& operator= (typename Container::const_reference value){
    container->push(value); return *this; }
  push_insert_iterator<Container>& operator* (){ return *this; }
  push_insert_iterator<Container>& operator++ (){ return *this; }
  push_insert_iterator<Container> operator++ (int){ return *this; }
};

I'd also add in the following function to help use it:

template<typename Container>
push_insert_iterator<Container> push_inserter(Container container){
    return push_insert_iterator<Container>(container);
}

Answer 2

The other alternative (simpler) is just to use the underlying data structure (std::stack is usually implemented using std::deque) and accept that you have to use eg push_back() instead of push(). Saves having to code your own iterator, and doesn't particularly affect the clarity of the code. std::stack isn't your only choice for modelling the stack concept.