An indexable container class. Elements can be accessed by their position in the container. Provides fast random access to elements. Additions to either the front or the back of a deque are efficient. Insertions into the middle are not efficient.

a "double-ended queue" that allows both addition and removal at each end. Icon lists are deques.

a combination of a vector and two queues, operating at both ends of the vector

a doubly-ended queue, which permits insertions and deletions at both the front and rear