C++

Suppose you have a deque D containing the numbers (1,2,3,4,5,6,7,8), in this order. Suppose further that you have an initially empty queue Q. Give a pseudo-code description of a function that uses only D and Q (and no other variables or objects) and results in D storing the elements (1,2,3,5,4,6,7,8), in this order.

Repeat the previous problem using the deque D and an initially empty stack S.

Please explain it for C++