Queue
Queue is the linear data structure which is able to perform operation in FIFO (First In First Out) way. utilict supports following methods on Queue:
| Method | Description | Returns |
|---|---|---|
enqueue(item) | Adds a new item in the rear of the queue. If the queue is full, it will throw an error. | void |
dequeue() | Removes the front item from the queue. If the queue is empty, it will throw an error. | Dequeued item |
getFront() | Returns the front element of the queue. | Front element |
getRear() | Returns the rear element of the queue. | Rear element |
isFull() | Checks if the queue is full. | true if the queue is full, otherwise false |
isEmpty() | Checks if the queue is empty. | true if the queue is empty, otherwise false |
length() | Returns the number of items in the queue. | Queue elements count |
search(item) | Searches for an item in the queue and returns its index. | If the element is present, it returns the index, otherwise -1 |
Usage
const queue = new Queue();
queue.enqueue(35); // Adds the value 35 from rear end of the queue.
queue.enqueue(76); // Adds the value 76 from rear end of the queue.
queue.length(); // Returns the element count, 2;
queue.getFront(); // Returns the front item, 35.
queue.getRear(); // Returns the rear item, 76.
queue.dequeue(); // Removes element 35 from front end and returns it.
queue.search(76); // Returns the position of the 76 is inserted in the queue, 1.
queue.dequeue(); // Removes element 76 from front end and returns it.
queue.getFront(); // Returns an error "Queue is empty".
// Queues can also be declared with a size.
const queueWithSize = new Queue(2); // This will create a queue with a size 2;
queueWithSize.enqueue(45); // Enqueue an item 45
queueWithSize.enqueue(43); // Enqueue an item 43
queueWithSize.isFull(); // Returns "true"
queueWithSize.enqueue(37); // As the queue is full now, it will throw the "queue is full" error.