#! /usr/bin/python3

from collections import deque

## ---- if you want to use the queue module
## ---- from queue import deque

lst = [ 'a', 'b', 'c' ]

stack = deque()

## ---- you can feed the complete list directly to deque
## ---- stack = deque(lst)

print()
print('--------------------------------------------')
print('---- LIFO (Last In First Out) --------------')
print('--------------------------------------------')
print(f'List: {lst}')
print()
stacka = deque()
for x in lst:
    print(f'stacka.appendleft {x}')
    stacka.appendleft(x)
print('--------------------------------------------')
for i in range(len(stacka)):
    print(f'stacka [{i}] {stacka[i]}')
print('--------------------------------------------')
while len(stacka) > 0:
    x = stacka.popleft()
    print(f'stacka.popleft {x}')
print()

print('--------------------------------------------')
print('---- LIFO (Last In First Out) --------------')
print('--------------------------------------------')
print(f'List: {lst}')
print()
stackb = deque()
for x in lst:
    print(f'stackb.append {x}')
    stackb.append(x)
print('--------------------------------------------')
for i in range(len(stackb)):
    print(f'stackb [{i}] {stackb[i]}')
print('--------------------------------------------')
while len(stackb) > 0:
    x = stackb.pop()
    print(f'stackb.pop {x}')
print()

print('--------------------------------------------')
print('---- FIFO (First In First Out) -------------')
print('--------------------------------------------')
print(f'List: {lst}')
print()
stackc = deque()
for x in lst:
    print(f'stackc.append {x}')
    stackc.append(x)
print('--------------------------------------------')
for i in range(len(stackc)):
    print(f'stackc [{i}] {stackc[i]}')
print('--------------------------------------------')
while len(stackc) > 0:
    x = stackc.popleft()
    print(f'stackc.popleft {x}')
print()

print('--------------------------------------------')
print('---- FIFO (First In First Out) -------------')
print('--------------------------------------------')
print(f'List: {lst}')
print()
stackd = deque()
for x in lst:
    print(f'stackd.appendleft {x}')
    stackd.appendleft(x)
print('--------------------------------------------')
for i in range(len(stackd)):
    print(f'stackd [{i}] {stackd[i]}')
print('--------------------------------------------')
while len(stackd) > 0:
    x = stackd.pop()
    print(f'stackd.pop {x}')
print()

--------------------------------------
---- LIFO (Last In First Out) --------
--------------------------------------
List: ['a', 'b', 'c']

stacka.appendleft a
stacka.appendleft b
stacka.appendleft c
--------------------------------------
stacka [0] c
stacka [1] b
stacka [2] a
--------------------------------------
stacka.popleft c
stacka.popleft b
stacka.popleft a

--------------------------------------
---- LIFO (Last In First Out) --------
--------------------------------------
List: ['a', 'b', 'c']

stackb.append a
stackb.append b
stackb.append c
--------------------------------------
stackb [0] a
stackb [1] b
stackb [2] c
--------------------------------------
stackb.pop c
stackb.pop b
stackb.pop a

--------------------------------------
---- FIFO (First In First Out) -------
--------------------------------------
List: ['a', 'b', 'c']

stackc.append a
stackc.append b
stackc.append c
--------------------------------------
stackc [0] a
stackc [1] b
stackc [2] c
--------------------------------------
stackc.popleft a
stackc.popleft b
stackc.popleft c

--------------------------------------
---- FIFO (First In First Out) -------
--------------------------------------
List: ['a', 'b', 'c']

stackd.appendleft a
stackd.appendleft b
stackd.appendleft c
--------------------------------------
stackd [0] c
stackd [1] b
stackd [2] a
--------------------------------------
stackd.pop a
stackd.pop b
stackd.pop c