**Queues** are just like a waiting list. Imagine a scenario where you have to withdraw cash from the bank and you stand in a line waiting for your turn -- this is a real-life example of a queue.

In Ruby, the implementation of `Queue` is similar to other *object-oriented languages* such as Java or Python.

# Implementation

Ruby on Rails has a built-in class `Queue` that implements multi-producer, multi-consumer queues. 

Some built-in methods in Ruby `Queue` Class include:

## `push()` and `pop()`in Queue

* `push()` - inserts the element in the queue 

* `pop()` - returns the element in the front of the queue and removes it from the queue
```
q1 = Queue.new
  q1.push(5)
  q1.push(6)
  puts q1.pop()
```

## `shift()` in Queue

* returns and removes the front element of the queue
```
q1 = Queue.new
  q1.push(5)
  q1.push(6)
  puts q1.shift()
```

## `close()` in Queue

* closes the queue permanently and does not allow any more push or pop operations 
> A closed queue cannot be re-opened. 

```
q1 = Queue.new
  q1.push(5)
  q1.push(6)
  q1.close() //closes the queue
  puts q1.close() //checks whether the queue is closed or not.
```

## `clear()` in Queue

* clears the queue and returns its size to zero

> We can also re-insert objects into the queue.

```
q1 = Queue.new
  q1.push(5)
  q1.push(6)
  q1.clear()
```

What are Queues in ROR?

Queues in Ruby on Rails allow multi-producer, multi-consumer operations and include methods like push(), pop(), shift(), close(), and clear() for management.

What are Queues in ROR?

Implementation

push() and pop()in Queue

shift() in Queue

close() in Queue

clear() in Queue

`push()` and `pop()`in Queue

`shift()` in Queue

`close()` in Queue

`clear()` in Queue