Python program to insert a new node at the beginning of the Circular Linked List
#Represents the node of list.
class Node:
def __init__(self,data):
self.data = data;
self.next = None;
class CreateList:
#Declaring head and tail pointer as null.
def __init__(self):
self.head = Node(None);
self.tail = Node(None);
self.head.next = self.tail;
self.tail.next = self.head;
#This function will add at the start of the list.
def addAtStart(self,data):
newNode = Node(data);
#Checks if the list is empty.
if self.head.data is None:
#If list is empty, both head and tail would point to new node.
self.head = newNode;
self.tail = newNode;
newNode.next = self.head;
else:
#Store data into temporary node
temp = self.head;
#New node will point to temp as next node
newNode.next = temp;
#New node will be the head node
self.head = newNode;
#Since, it is circular linked list tail will point to head.
self.tail.next = self.head;
#Displays all the nodes in the list
def display(self):
current = self.head;
if self.head is None:
print("List is empty");
return;
else:
print("Adding nodes to the start of the list: ");
#Prints each node by incrementing pointer.
print(current.data),
while(current.next != self.head):
current = current.next;
print(current.data),
print("\n");
class CircularLinkedList:
cl = CreateList();
#Adding 1 to the list
cl.addAtStart(1);
cl.display();
#Adding 2 to the list
cl.addAtStart(2);
cl.display();
#Adding 3 to the list
cl.addAtStart(3);
cl.display();
#Adding 4 to the list
cl.addAtStart(4);
cl.display();
Output:
Adding nodes to the start of the list:
1
Adding nodes to the start of the list:
2 1
Adding nodes to the start of the list:
3 2 1
Adding nodes to the start of the list:
4 3 2 1
