Structure of a linked list based queue

Going back to the definition of a queue, it is a linear data structure that only supports enqueue and dequeue operations to add and remove data items from the back and front of the end of the queue, respectively. Like an array, a linked list is another data structure that is the perfect candidate for implementing a queue. Unlike arrays, which have a fixed size and are used to implement bounded queues, linked lists can be as big as the computer memory permits, so they can be used to implement an unbounded queue. 

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