Is there a way to access the underlying container of STL container adaptors?
c++, data-structures, standards, stl
Solution
I spotted the following solution somewhere on the web and I'm using it in my projects:
template <class T, class S, class C>
S& Container(priority_queue<T, S, C>& q) {
struct HackedQueue : private priority_queue<T, S, C> {
static S& Container(priority_queue<T, S, C>& q) {
return q.*&HackedQueue::c;
}
};
return HackedQueue::Container(q);
}
int main()
{
priority_queue<SomeClass> pq;
vector<SomeClass> &tasks = Container(pq);
return 0;
}
Have fun :).
Problem
Is there a standard way to access the underlying container of `stack`, `queue`, `priority_queue` ? I found a method called : `_Get_container()` in `VS2008` implementation of `stack` and `queue`, but no one for `priority_queue`! I think it is not standard anyway. Also, I know it is a silly question! where can I find official documentation of the standard library ? Just for clarification, I wasn't trying to mess up with the underlying container. All what I was trying to do is this : ``` template <class Container> std::ostream& printOneValueContainer(std::ostream& outputstream, Container& container) { Container::const_iterator beg = container.begin(); outputstream << "["; while(beg != container.end()) { outputstream << " " << *beg++; } outputstream << " ]"; return outputstream; } // stack, queue template < class Type , template<class Type, class Container = std::deque<Type> > class Adapter > std::ostream& operator<<(std::ostream& outputstream, const Adapter<Type>& adapter) { return printOneValueContainer(outputstream, adapter._Get_container()); } . . . std::stack<int> iStack; . . std::cout << iStack << std::endl; ``` I hope you see that `_Get_container()` is not standard, and there is no one for `priority_queue` in `VS2008` implementation.