LinkedCircularQueue.py

class Node:
	def __init__(self):
		self.data = None
		self.link = None

class Queue:
	def __init__(self):
		front = None
		rear = None

# Function to create Circular queue
def enQueue(q, value):
	temp = Node()
	temp.data = value
	if (q.front == None):
		q.front = temp
	else:
		q.rear.link = temp

	q.rear = temp
	q.rear.link = q.front

def deQueue(q):
	if (q.front == None):
		print("Queue is empty")
		return -999999999999

	# If this is the last node to be deleted
	value = None # Value to be dequeued
	if (q.front == q.rear):
		value = q.front.data
		q.front = None
		q.rear = None
	else: # There are more than one nodes
		temp = q.front
		value = temp.data
		q.front = q.front.link
		q.rear.link = q.front

	return value

def displayQueue(q):
	temp = q.front
	print("Elements in Circular Queue are: ",
								end = " ")
	while (temp.link != q.front):
		print(temp.data, end = " ")
		temp = temp.link
	print(temp.data)

# Driver Code
if __name__ == '__main__':

	# Create a queue and initialize
	# front and rear
	q = Queue()
	q.front = q.rear = None

	# Inserting elements in Circular Queue
	enQueue(q, 14)
	enQueue(q, 22)
	enQueue(q, 6)

	# Display elements present in
	# Circular Queue
	displayQueue(q)

	# Deleting elements from Circular Queue
	print("Deleted value = ", deQueue(q))
	print("Deleted value = ", deQueue(q))

	# Remaining elements in Circular Queue
	displayQueue(q)

	enQueue(q, 9)
	enQueue(q, 20)
	displayQueue(q)