Or just use recursion(implicit stack).

Pop everything into a sorted map/tree?

Using the same queue, do "bubble sort" length(queue) times: void bubbleSortQueue(std::queue* toSort ) { int length = toSort->size(); if (length front(); toSort->pop(); for (int currItem = 0; currItem front(); toSort->pop(); if (first > second) { toSort->push(second); } else { toSort->push(first); first = second; } } toSort->push(first); } }