c++ deque vs queue vs stack

Queue: you can insert only in one end and remove from the other.

Deque: you can insert and remove from both ends.

So using a Deque, you can model a Queue as well as a Stack.

Hint:
Deque is short for "Double ended queue".

Moron/Aryabhatta is correct, but a little more detail may be helpful.

Queue and stack are higher level containers than deque, vector, or list. By this, I mean that you can build a queue or stack out of the lower level containers.

For example:

  std::stack<int, std::deque<int> > s;
  std::queue<double, std::list<double> > q;

Will build a stack of ints using a deque as the underlying container and a queue of doubles using a list as the underlying container.

You can think of s as a restricted deque and q as a restricted list.

All that is necessary is that the lower level container implements the methods needed by the higher level container. These are back(), push_back(), and pop_back() for stack and front(), back(), push_back(), and pop_front() for queue.

See stack and queue for more detail.

With respect to the deque, it is much more than a queue where you can insert at both ends. In particular, it has the random access operator[]. This makes it more like a vector, but a vector where you can insert and delete at the beginning with push_front() and pop_front().

See deque for detail.