Working with queues

Like stacks, queues are collections of elements or objects of the same type. The length of any queue is variable just like a stack, meaning its size changes as elements are added or removed. However, queues follow the first-in-first-out (FIFO) model, meaning the first element in the queue is the first accessible element. You should note that queues can store null and duplicate values but can't be initialized with elements when they're created.