In computer science, a double-ended queue (abbreviated to deque — DEK), is an abstract data type that serves as a container, with a restricted access to the stored items. As a generalization of both the stack and the queue, the deque may have similar functions as a data buffer: it can be use both as a retainer (queue), or for backtracking (stack). However it offers greater flexibility in managing the order of elements and some algorithms are based on its functionalities.