A Deque is bassically a type of vector .It is like a double-ended vector, It inherits the vector container class�s efficiency in sequential read and write operations. But in case of addition, the deque container class provides optimized front-end and back-end operations. These type of operations are same as implemented they are in the list container class, where memory allocations are engaged only for new elements. This feature of the deque class eliminates the need to reallocate the whole container to a new memory location, as the vector class has to do. Even deques are ideally suited for applications in which insertions and deletions take place at either one or both ends, and for which sequential access of elements is important.