Program 1
# Implementation of circular double linked list
import os
class Node:
def __init__(self):
self.ladd=None
self.data=None
self.radd=None
class CircularDoubleList:
def __init__(self):
self.start=None
self.count=0
def create(self):
n=int(input("Enter first element: "))
self.start=Node()
self.start.ladd=None
self.start.data=n
self.start.radd=None
temp=self.start
self.count=self.count+1
choice=input("Want to continue(y/Y): ")
choice=choice.lower()
while(choice=='y'):
self.count=self.count+1
n=int(input("Enter next element: "))
newnode=Node()
newnode.ladd=None
newnode.data=n
newnode.radd=None
temp.radd=newnode
newnode.ladd=temp
temp=temp.radd
self.start.ladd=newnode
newnode.radd=self.start
choice=input("Want to continue(y/Y): ")
choice=choice.lower()
def display(self):
if(self.start==None):
print("List is empty")
else:
temp=self.start
while(True):
print(temp.data,end=" ")
temp=temp.radd
if(temp==self.start):
break
print("\n Total Node in list: ",self.count)
def insertFirst(self):
if(self.start==None):
print("List is empty")
else:
self.count=self.count+1
n=int(input("Enter next element: "))
newnode=Node()
newnode.ladd=None
newnode.data=n
newnode.radd=None
last=self.start.ladd
self.start.ladd=newnode
newnode.radd=self.start
self.start=newnode
self.start.ladd=last
last.radd=self.start
def insertMiddle(self):
if(self.start==None):
print("List is empty")
else:
self.count=self.count+1
n=int(input("Enter an element: "))
newnode=Node()
newnode.ladd=None
newnode.data=n
newnode.radd=None
pos=int(input("Enter poistion of node: "))
if(pos>self.count):
print("Poistion is grater than total node: ")
else:
i=1
next=self.start
while(i<pos):
prev=next
next=next.radd
i=i+1
prev.radd=newnode
newnode.ladd=prev
newnode.radd=next
next.ladd=newnode
def insertLast(self):
if(self.start==None):
print("List is empty")
else:
self.count=self.count+1
n=int(input("Enter an element: "))
newnode=Node()
newnode.ladd=None
newnode.data=n
newnode.radd=None
last=self.start.ladd
last.radd=newnode
newnode.ladd=last
self.start.ladd=newnode
newnode.radd=self.start
def deleteFirst(self):
if(self.start==None):
print("List is empty")
else:
temp=self.start
last=self.start.ladd
self.start=self.start.radd
self.start.ladd=last
last.radd=self.start
print(" Deleted node is ",temp.data)
del temp
temp=None
self.count=self.count-1
def deleteLast(self):
if(self.start==None):
print("List is empty")
else:
last=self.start.ladd
prev=last.ladd
self.start.ladd=prev
prev.radd=self.start
print("Deleted node is : ",last.data)
del last
last=None
self.count=self.count-1
def deleteMiddle(self):
if(self.start==None):
print("List is empty")
else:
pos=int(input("Enter poistion of node for delete: "))
if(pos>self.count):
print("Poistion is grater than total node: ")
else:
self.count=self.count-1
i=1
next=self.start
while(i<pos):
prev=next
next=next.radd
i=i+1
temp=next
next=next.radd
next.ladd=prev
prev.radd=next
print("Deleted node is : ",temp.data)
del temp
temp=None
# Main
os.system('cls')
cdll=CircularDoubleList()
while(1):
print("\n --------------------DoubleLinked List------------------------")
print("1. Create")
print("2. Display")
print("3. Insert First")
print("4. Insert Middle")
print("5. Insert Last")
print("6. Delete First ")
print("7. Delete Middle ")
print("8. Delete Last ")
print("9. Exit")
print("---------------------------------------------------------")
choice=int(input("Enter your choice: "))
if(choice==1):
cdll.create()
elif(choice==2):
cdll.display()
elif(choice==3):
cdll.insertFirst()
elif(choice==4):
cdll.insertMiddle()
elif(choice==5):
cdll.insertLast()
elif(choice==6):
cdll.deleteFirst()
elif(choice==7):
cdll.deleteMiddle()
elif(choice==8):
cdll.deleteLast()
else:
break
