Singly Linked List in DSA Python

Program 1

# Implementation of single linked list
import os
class Node:
    def __init__(self):
        self.data=None
        self.add=None

class LinkedList:
    def __init__(self):
        self.start=None
        self.count=0

    def create(self):
        n=int(input("Enter First element: "))    
        self.start=Node()
        self.start.data=n
        self.start.add=None
        self.temp=self.start
        self.count=self.count+1
        ch=input("Wan to continue(Y/y): ")
        while(ch=='y' or ch=='Y'):
            self.count=self.count+1
            n=int(input("Enter next element: "))    
            newnode=Node()
            newnode.data=n   # assign data to new node
            newnode.add=None # assign address to new node
            self.temp.add=newnode 
            self.temp=self.temp.add
            ch=input("Wan to continue(Y/y): ")

    def display(self):
        if(self.start==None):
            print("List is empty")
        else:    
            print("Elements of List: ")      
            self.temp=self.start
            while(self.temp!=None):
                print(self.temp.data,end="  ")
                self.temp=self.temp.add

            print("\n Total Node is : ",self.count)                    

    def insertFirst(self):
        if(self.start==None):
            print("List is empty")
        else:
            self.count=self.count+1
            n=int(input("Enter an element for insert: "))            
            newnode=Node()
            newnode.data=n
            newnode.add=None
            newnode.add=self.start
            self.start=newnode

    def insertMiddle(self):  
        if(self.start==None):
            print("List is empty")
        else:
            self.count=self.count+1
            n=int(input("Enter an element for insert: "))            
            newnode=Node()
            newnode.data=n
            pos=int(input("Enter node position for insert:  "))      
            i=1
            next=self.start
            while(i<pos): 
                prev=next
                next=next.add
                i=i+1
            prev.add=newnode
            newnode.add=next


    def insertLast(self):     
        if(self.start==None):
            print("List is empty")
        else:
            self.count=self.count+1
            n=int(input("Enter an element for insert: "))            
            newnode=Node()
            newnode.data=n
            last=self.start
            while(last.add!=None):
                last=last.add 
            last.add=newnode                  

    def deleteFirst(self):
        if(self.start==None):
            print("List is empty")
        else:
            self.count=self.count-1
            self.temp=self.start
            self.start=self.start.add
            print("Deleted node is : ",self.temp.data)
            del self.temp


    def deleteMiddle(self):
         if(self.start==None):
            print("List is empty")
         else:
            self.count=self.count-1
            i=1
            pos=int(input("Enter node position for delete: "))
            next=self.start
            while(i<pos):
                prev=next
                next=next.add
                i=i+1

            self.temp=next
            next=next.add  

            prev.add=next
            print("Deleted node is : ",self.temp.data)  
            del self.temp
            

    def deleteLast(self):
        if(self.start==None):
            print("List is empty")
        else:
            self.count=self.count-1
            self.temp=self.start
            while(self.temp.add!=None):
                   last=self.temp
                   self.temp=self.temp.add

            print("Deleted Node is : ",self.temp.data)                   
            last.add=None
            del self.temp
            self.temp=None

    def countNode(self):
        if(self.start==None):
            print("List is empty")
        else:
            print("Total Node is : ",self.count)




# Main
os.system('cls')
mylist=LinkedList()
while(1):
    print("\n --------------------Linked 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. Count Node ")
    print("10. Exit")
    print("---------------------------------------------------------")
    choice=int(input("Enter your choice: "))
    if(choice==1):
        mylist.create()
    elif(choice==2):
        mylist.display()
    elif(choice==3):
        mylist.insertFirst()        
    elif(choice==4):
        mylist.insertMiddle()            
    elif(choice==5):
        mylist.insertLast()            
    elif(choice==6):
        mylist.deleteFirst()
    elif(choice==7):
        mylist.deleteMiddle()
    elif(choice==8):
        mylist.deleteLast()    
    elif(choice==9):
        mylist.countNode()        
    else:
        break