Queue

a queue is open at both its ends. One end is always used to insert data (enqueue) and the other is used to remove data (dequeue). Queue follows First-In-First-Out methodology.

A real-world example of queue can be a single-lane one-way road, where the vehicle enters first, exits first. More real-world examples can be seen as queues at the ticket windows and bus-stops.

As in stacks, a queue can also be implemented using Arrays, Linked-lists, Pointers and Structures. For the sake of simplicity, we shall implement queues using one-dimensional array.

Basic Operations

• enqueue() − add (store) an item to the queue.

  

• dequeue() − remove (access) an item from the queue.

  

Few more functions are required to make the above-mentioned queue operation efficient. These are −>

• peek() − Gets the element at the front of the queue without removing it.
• isfull() − Checks if the queue is full.
• isempty() − Checks if the queue is empty.