11import os
2- 32class _Node :
3+ '''
4+ Creates a Node with two fields:
5+ 1. element (accesed using ._element)
6+ 2. link (accesed using ._link)
7+ '''
48 __slots__ = '_element' , '_link'
5- 69 def __init__ (self , element , link ):
10+ '''
11+ Initialses _element and _link with element and link respectively.
12+ '''
713 self ._element = element
814 self ._link = link
915
1016class CicularLL :
17+ '''
18+ Consists of member funtions to perform different
19+ operations on the circular linked list.
20+ '''
1121 def __init__ (self ):
22+ '''
23+ Initialses head, tail and size with None, None and 0 respectively.
24+ '''
1225 self ._head = None
1326 self ._tail = None
1427 self ._size = 0
1528
1629 def __len__ (self ):
30+ '''
31+ Returns length of linked list
32+ '''
1733 return self ._size
1834
1935 def isempty (self ):
36+ '''
37+ Returns True if circular linked list is empty, otherwise False.
38+ '''
2039 return self ._size == 0
2140
2241 def addLast (self , e ):
42+ '''
43+ Adds the passed element at the end of the circular linked list.
44+ '''
2345 newest = _Node (e , None )
2446
2547 if self .isempty ():
@@ -33,6 +55,9 @@ def addLast(self, e):
3355 self ._size += 1
3456
3557 def addFirst (self , e ):
58+ '''
59+ Adds the passed element at the beginning of the circular linked list.
60+ '''
3661 newest = _Node (e , None )
3762
3863 newest ._link = self ._head
@@ -46,6 +71,9 @@ def addFirst(self, e):
4671 self ._size += 1
4772
4873 def addAnywhere (self , e , index ):
74+ '''
75+ Adds the passed element at the passed index position of the circular linked list.
76+ '''
4977 newest = _Node (e , None )
5078 if index >= self ._size :
5179 print (
@@ -66,6 +94,10 @@ def addAnywhere(self, e, index):
6694 self ._size += 1
6795
6896 def removeFirst (self ):
97+ '''
98+ Removes element from the beginning of the circular linked list.
99+ Returns the removed element.
100+ '''
69101 if self .isempty ():
70102 print ("List is Empty" )
71103 return
@@ -77,6 +109,10 @@ def removeFirst(self):
77109 return e
78110
79111 def removeLast (self ):
112+ '''
113+ Removes element from the end of the circular linked list.
114+ Returns the removed element.
115+ '''
80116 if self .isempty ():
81117 print ("List is Empty" )
82118 return
@@ -95,7 +131,10 @@ def removeLast(self):
95131 return e
96132
97133 def removeAnywhere (self , index ):
98- 134+ '''
135+ Removes element from the passed index position of the circular linked list.
136+ Returns the removed element.
137+ '''
99138 if index >= self ._size :
100139 print (
101140 f"Index out of range. It should be between 0 - { self ._size - 1 } )
@@ -118,6 +157,9 @@ def removeAnywhere(self, index):
118157 return e
119158
120159 def display (self ):
160+ '''
161+ Utility function to display the circular linked list.
162+ '''
121163 if self .isempty () == 0 :
122164 p = self ._head
123165 while True :
@@ -131,8 +173,10 @@ def display(self):
131173
132174#########################################################################
133175
134- 135176def options ():
177+ '''
178+ Prints Menu for operations
179+ '''
136180 options_list = ['Add Last' , 'Add First' , 'Add Anywhere' ,
137181 'Remove First' , 'Remove Last' , 'Remove Anywhere' ,
138182 'Display List' , 'Exit' ]
@@ -146,6 +190,9 @@ def options():
146190
147191
148192def switch_case (choice ):
193+ '''
194+ Switch Case for operations
195+ '''
149196 os .system ('cls' )
150197 if choice == 1 :
151198 elem = int (input ("Enter Item: " ))
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