the queue element
Type: the internal queue to store elements
Returns a new blank internal queue to store elements
The internal queue to store elements
The first element in the queue
Number of elements in the queue
Returns an iterator over the queue elements
Clears the queue
Creates a new queue based on the current one and returns it
Removes the head element from the queue and returns it
Adds a new element to the queue
Alias to pop
Alias to push
Returns an iterator over the queue elements
Implementation of a queue data structure based on a linked-list