# Author : Raed Ahsan
# Date : 22.06.2022
# Time : 9:37 PM

#Queue ADT ( CIRCULAR )

# Initialization
frontpointer = -1 
rearpointer  = -1
Qsize = 0
Qfull = 10
ub = 9

queue = [None for x in range(9)]

def initializeQ():
  frontpointer = -1
  rearpointer = -1
  Qsize = 0
  Qfull = 10
  ub = 9

  for i in range(9):
    queue[i] = None

# Enqueue ( INSERTION ) - REARPOINTER : 

def enqueue(data):
  global Qsize, Qfull, rearpointer, ub
  if Qsize == Qfull:

    print("[!]--Overflow Error") 
  else:
    if rearpointer == ub:
      rearpointer = 0
    else:
      rearpointer = rearpointer + 1

    queue[rearpointer] = data
    Qsize = Qsize + 1


# Dequeue ( DELETION ) - FRONTPOINTER : 

def dequeue():
  global frontpointer, ub, Qsize

  if Qsize == 0:
    print("[!] Underflow error, no sufficient values.")
  else:
    if frontpointer == ub:
      frontpointer = 0
    else:
      frontpointer = frontpointer + 1

    print("Data Dequeued: ", queue[frontpointer])
    Qsize = Qsize - 1

# Printing live values for the queue ADT circular function..

def live_track():
  global rearpointer, frontpointer, Qsize
  print("RearPointer Location: ", rearpointer)
  print("FrontPointer Location: ", frontpointer)
  print("The Qsize filled: ", Qsize + 1)
  print(queue)
  queue[frontpointer] = None

# Final execution test:
#enqueue:

# enqueue('a')
# live_track()
# enqueue('b')
# live_track()
# enqueue('c')
# live_track()
# enqueue('d')
# live_track()

#dequeue:

# dequeue()
# live_track()
# dequeue()
# live_track()
# dequeue()
# live_track()
# dequeue()
# live_track()