diff --git a/01. singlylinkedlist.cpp b/01. singlylinkedlist.cpp
new file mode 100644
index 00000000..2bd4196d
--- /dev/null
+++ b/01. singlylinkedlist.cpp	
@@ -0,0 +1,298 @@
+
+//// happy coding ////
+//// chant hare krishna /////
+//// rk dagar ///////
+
+#include<bits/stdc++.h>
+using namespace std;
+
+class node{
+	public:
+		int data;
+		node *next;
+};
+
+node *start = NULL;
+node *createll(node *);
+node *display(node *);
+node *insertbeg(node *);
+node *insertend(node *);
+node *insertbefore(node *);
+node *insertafter(node *);
+node *deletebeg(node *);
+node *deleteend(node *);
+node *deletenode(node *);
+node *deleteafter(node *);
+node *deletelist(node *);
+node *sortll(node *);
+int main()
+{
+	int option;
+	do{
+		cout<<"\n\n *******MAIN MENU*******";
+		cout<<"\n 1:  Create a list ";
+		cout<<"\n 2:  Display the list ";
+		cout<<"\n 3:  Add a node at the begining";
+		cout<<"\n 4:  Add a node at the end";
+		cout<<"\n 5:  Add a node before a given node";
+		cout<<"\n 6:  Add a node after a given node";
+		cout<<"\n 7:  delete a node from the begining";
+		cout<<"\n 8:  delete a node from the end";
+		cout<<"\n 9:  delete a given node";
+		cout<<"\n 10: delete a node after given node";
+		cout<<"\n 11: delete entire list";
+		cout<<"\n 12: sort the list";
+		cout<<"\n 13: exit\n";
+		cin>>option;
+		switch(option)
+		{
+			case 1:
+				start= createll(start);
+				cout<<"\n linked list created";
+				break;
+			case 2:
+				start= display(start);
+				break;
+		    case 3:
+		    	start= insertbeg(start);
+		    	break;
+		    case 4:
+		    	start= insertend(start);
+		    	break;
+		    case 5:
+		    	start= insertbefore(start);
+		    	break;
+		    case 6:
+		    	start= insertafter(start);
+		    	break;
+		    case 7:
+		    	start= deletebeg(start);
+		    	break;
+		    case 8:
+		    	start= deleteend(start);
+		    	break;
+		    case 9:
+		    	start= deletenode(start);
+		    	break;
+		    case 10:
+		    	start= deleteafter(start);
+		    	break;
+		    case 11:
+		    	start= deletelist(start);
+		    	cout<<"\n linked list deleted";
+		    	break;
+		    case 12:
+		    	start= sortll(start);
+		    	break;
+		     
+		}
+	}while(option!=13);
+	
+	return 0;
+}
+
+node* createll(node *start)
+{
+	node* nn,*p;
+	int num;
+	cout<<"\nenter -1 to end\n";
+	cin>>num;
+	while(num!=-1)
+	{
+		nn=new node();
+		nn->data=num;
+		nn->next=NULL;
+		if(start==NULL)
+		{		
+		    start=nn;
+		}
+		else
+		{
+			p=start;
+			while(p->next!=NULL)
+				p=p->next;
+			p->next=nn;
+		}
+		cin>>num;
+	}
+	return start;
+}
+node *display(node* start)
+{
+	node *t=start;
+	while(t!=NULL)
+	{
+		cout<<t->data<<" -> ";
+		t=t->next;
+	}
+	cout<<"NULL\n";
+	return start;
+}
+
+node *insertbeg(node *start)
+{
+	node *nn= new node();
+	int num;
+	cin>>num;
+	nn->data=num;
+	nn->next=start;
+	start=nn;
+	
+	return start;
+}
+
+node *insertend(node *start)
+{
+	node *nn=new node();
+	node *p=start;
+	int num;
+	cin>>num;
+	nn->data=num;
+	nn->next=NULL;
+	while(p->next!=NULL)
+	{
+		p=p->next;
+	}
+	p->next=nn;
+	
+	
+	return start;
+	
+	
+}
+node *insertbefore(node *start)
+{
+	node *nn= new node();
+	node *p=start;
+	node *preptr;
+	int num,val;
+	cin>>num>>val;
+	nn->data=num;
+	while(p->data!=val)
+	{
+		preptr=p;
+		p=p->next;
+	}
+	preptr->next=nn;
+	nn->next=p;
+	
+	return start;
+	
+}
+
+node *insertafter(node *start)
+{
+	node *nn=new node();
+	node *p= start,*pre=start;
+	int num,val;
+	cin>>num>>val;
+	nn->data=num;
+	while(pre->data!=val)
+	{
+		pre= p;
+		p=p->next;
+	}
+nn->next=p;
+pre->next=nn;
+
+return start;
+}
+
+node *deletebeg(node *start)
+{
+	node *nn;
+	nn= start;
+	start=nn->next;
+	free(nn);
+	
+	return start;
+}
+
+node *deleteend(node *start)
+{
+	node *nn=start,*p;
+	while(nn->next!=NULL)
+	{
+		p=nn;
+		nn=nn->next;
+	}
+	p->next=NULL;
+	free(nn);
+	
+	return start;
+}
+
+node *deletenode(node *start)
+{
+	int val;
+	cin>>val;
+	node *p=start,*pre;
+	while(p->data==val) 
+	{
+		start= deletebeg(start);
+	return start;
+}
+while(p->data!=val)
+{
+	pre=p;
+	p=p->next;
+}
+pre->next=p->next;
+free(p);
+
+return start;
+	
+}
+
+node *deleteafter(node *start)
+{
+	node *nn,*p=start;
+	nn=start;
+	int num;
+	cin>>num;
+	while(p->data!=num)
+	{
+		p=nn;
+		nn=nn->next;
+	}
+	p->next=nn->next;
+	free(nn);
+	
+	return start;
+}
+
+node *deletelist(node *start)
+{
+	node *n=start;
+	while(n!=NULL)
+	{
+		start= deletebeg(start);
+		n=start;
+	}
+	
+	return start;
+}
+
+node *sortll(node *start)
+{
+	node *p1,*p2;
+	int t;
+	p1=start;
+	while(p1->next!=NULL)
+	{
+		p2=p1->next;
+		while(p2!=NULL)
+		{
+			if(p1->data>p2->data)
+			{
+				t=p1->data;
+				p1->data=p2->data;
+				p2->data=t;
+			}
+			p2=p2->next;
+		}
+		p1=p1->next;
+	}
+	return start;
+}
+
diff --git a/02. circular singly linked list.cpp b/02. circular singly linked list.cpp
new file mode 100644
index 00000000..087b8b82
--- /dev/null
+++ b/02. circular singly linked list.cpp	
@@ -0,0 +1,314 @@
+/*
+     hare krishna hare krishna krishna krishna hare hare
+     hare rama hare rama rama rama hare
+*/
+
+//// happy coding ////
+//// chant hare krishna /////
+//// ritik dagar ///////
+
+#include<bits/stdc++.h>
+using namespace std;
+
+class node{
+	public:
+		int data;
+		node *next;
+};
+
+node *start = NULL;
+node *createll(node *);
+node *display(node *);
+node *insertbeg(node *);
+node *insertend(node *);
+node *insertbefore(node *);
+node *insertafter(node *);
+node *deletebeg(node *);
+node *deleteend(node *);
+node *deletenode(node *);
+node *deleteafter(node *);
+node *deletelist(node *);
+node *sortll(node *);
+int main()
+{
+	int option;
+	cout<<"hare krishna hare krishna\nkrishna krishna hare hare\nhare rama hare rama\nrama rama hare hare\n";
+	cout<<"implementation of circular linked list\n";
+	do{
+		cout<<"\n\n *******MAIN MENU*******";
+		cout<<"\n 1:  Create a list ";
+		cout<<"\n 2:  Display the list ";
+		cout<<"\n 3:  Add a node at the begining";
+		cout<<"\n 4:  Add a node at the end";
+		cout<<"\n 5:  Add a node before a given node";
+		cout<<"\n 6:  Add a node after a given node";
+		cout<<"\n 7:  delete a node from the begining";
+		cout<<"\n 8:  delete a node from the end";
+		cout<<"\n 9:  delete a given node";
+		cout<<"\n 10: delete a node after given node";
+		cout<<"\n 11: delete entire list";
+		cout<<"\n 12: sort the list";
+		cout<<"\n 13: exit\n";
+		cin>>option;
+		switch(option)
+		{
+			case 1:
+				start= createll(start);
+				cout<<"\ncircular linked list created";
+				break;
+			case 2:
+				start= display(start);
+				break;
+		    case 3:
+		    	start= insertbeg(start);
+		    	break;
+		    case 4:
+		    	start= insertend(start);
+		    	break;
+		    case 5:
+		    	start= insertbefore(start);
+		    	break;
+		    case 6:
+		    	start= insertafter(start);
+		    	break;
+		    case 7:
+		    	start= deletebeg(start);
+		    	break;
+		    case 8:
+		    	start= deleteend(start);
+		    	break;
+		    case 9:
+		    	start= deletenode(start);
+		    	break;
+		    case 10:
+		    	start= deleteafter(start);
+		    	break;
+		    case 11:
+		    	start= deletelist(start);
+		    	cout<<"\ncircular linked list deleted";
+		    	break;
+		    case 12:
+		    	start= sortll(start);
+		    	break;
+		     
+		}
+	}while(option!=13);
+	
+	return 0;
+}
+
+node* createll(node *start)
+{
+	node* nn,*p;
+	int num;
+	cout<<"\nenter -1 to end\n";
+	cin>>num;
+	while(num!=-1)
+	{
+		nn=new node();
+		nn->data=num;
+		if(start==NULL)
+		{
+		    nn->next=nn;	
+		    start=nn;
+		}
+		else
+		{
+			p=start;
+			while(p->next!=start)
+				p=p->next;
+			p->next=nn;
+			nn->next=start;
+		}
+		cin>>num;
+	}
+	return start;
+}
+node *display(node* start)
+{
+	node *t=start;
+	while(t->next!=start)
+	{
+		cout<<t->data<<" -> ";
+		t=t->next;
+	}
+	cout<<t->data<<"\n";
+	return start;
+}
+
+node *insertbeg(node *start)
+{
+	node *p,*nn= new node();
+	int num;
+	cin>>num;
+	p=start;
+	while(p->next!=start)
+	p=p->next;
+	p->next=nn;
+	nn->data=num;
+	nn->next=start;
+	start=nn;
+	
+	return start;
+}
+
+node *insertend(node *start)
+{
+	node *nn=new node();
+	node *p=start;
+	int num;
+	cin>>num;
+	nn->data=num;
+	nn->next=start;
+	while(p->next!=start)
+	{
+		p=p->next;
+	}
+	p->next=nn;
+	
+	
+	return start;
+	
+	
+}
+node *insertbefore(node *start)
+{
+	node *nn= new node();
+	node *p=start;
+	node *preptr;
+	int num,val;
+	cin>>num>>val;
+	nn->data=num;
+	while(p->data!=val)
+	{
+		preptr=p;
+		p=p->next;
+	}
+	preptr->next=nn;
+	nn->next=p;
+	
+	return start;
+	
+}
+
+node *insertafter(node *start)
+{
+	node *nn=new node();
+	node *p= start,*pre=start;
+	int num,val;
+	cin>>num>>val;
+	nn->data=num;
+	while(pre->data!=val)
+	{
+		pre= p;
+		p=p->next;
+	}
+nn->next=p;
+pre->next=nn;
+
+return start;
+}
+
+node *deletebeg(node *start)
+{
+	node *nn;
+	nn= start;
+	while(nn->next!=start)
+	nn= nn->next; 
+	nn->next=start->next;
+	free(start);
+	start=nn->next;
+	
+	
+	return start;
+}
+
+node *deleteend(node *start)
+{
+	node *nn=start,*p;
+	while(nn->next!=start)
+	{
+		p=nn;
+		nn=nn->next;
+	}
+	p->next=nn->next;
+	free(nn);
+	
+	return start;
+}
+
+node *deletenode(node *start)
+{
+	int val;
+	cin>>val;
+	node *p=start,*pre;
+	while(p->data==val) 
+	{
+		start= deletebeg(start);
+	return start;
+}
+while(p->data!=val)
+{
+	pre=p;
+	p=p->next;
+}
+pre->next=p->next;
+free(p);
+
+return start;
+	
+}
+
+node *deleteafter(node *start)
+{
+	node *nn,*p;
+	nn=start;
+	p=nn;
+	int num;
+	cin>>num;
+	while(p->data!=num)
+	{
+		p=nn;
+		nn=nn->next;
+	}
+	p->next=nn->next;
+	if(nn==start)
+	start=p->next;
+	free(nn);
+	
+	return start;
+}
+
+node *deletelist(node *start)
+{
+	node *n=start;
+	while(n->next!=start)
+	{
+		start= deleteend(start);
+	}
+	free(start);
+	return start;
+}
+
+node *sortll(node *start)
+{
+	node *p1,*p2;
+	int t;
+	p1=start;
+	while(p1->next!=start)
+	{
+		p2=p1->next;
+		while(p2!=start)
+		{
+			if(p1->data>p2->data)
+			{
+				t=p1->data;
+				p1->data=p2->data;
+				p2->data=t;
+			}
+			p2=p2->next;
+		}
+		p1=p1->next;
+	}
+	return start;
+}
diff --git a/03. doubly linked list.cpp b/03. doubly linked list.cpp
new file mode 100644
index 00000000..d4501d08
--- /dev/null
+++ b/03. doubly linked list.cpp	
@@ -0,0 +1,310 @@
+/*
+     hare krishna hare krishna krishna krishna hare hare
+     hare rama hare rama rama rama hare
+*/
+
+//// happy coding ////
+//// chant hare krishna /////
+//// ritik dagar ///////
+
+#include<bits/stdc++.h>
+using namespace std;
+
+class node{
+	public:
+		int data;
+		node *prev;
+		node *next;
+		node()
+		{
+			data=0;
+			prev=next=NULL;
+		}
+		node(int n)
+		{
+			data=n;
+			prev=NULL;
+			next=NULL;
+		}
+};
+int num,val;
+node *start = NULL;
+node *createll(node *);
+node *display(node *);
+node *insertbeg(node *);
+node *insertend(node *);
+node *insertbefore(node *);
+node *insertafter(node *);
+node *deletebeg(node *);
+node *deleteend(node *);
+node *deletenode(node *);
+node *deleteafter(node *);
+node *deletebefore(node *);
+node *deletelist(node *);
+node *sortll(node *);
+int main()
+{
+	int option;
+	cout<<"hare krishna hare krishna\nkrishna krishna hare hare\nhare rama hare rama\nrama rama hare hare\n";
+	cout<<"representation of doubly linked list\n";
+	do{
+		cout<<"\n\n *******MAIN MENU*******";
+		cout<<"\n 1:  Create a list ";
+		cout<<"\n 2:  Display the list ";
+		cout<<"\n 3:  Add a node at the begining";
+		cout<<"\n 4:  Add a node at the end";
+		cout<<"\n 5:  Add a node before a given node";
+		cout<<"\n 6:  Add a node after a given node";
+		cout<<"\n 7:  delete a node from the begining";
+		cout<<"\n 8:  delete a node from the end";
+		cout<<"\n 9:  delete a given node";
+		cout<<"\n 10: delete a node after given node";
+		cout<<"\n 11: delete a node before given node";
+		cout<<"\n 12: delete entire list";
+		cout<<"\n 13: sort the list";
+		cout<<"\n 14: exit\n";
+		cin>>option;
+		switch(option)
+		{
+			case 1:
+				start= createll(start);
+				cout<<"\n linked list created";
+				break;
+			case 2:
+				start= display(start);
+				break;
+		    case 3:
+		    	start= insertbeg(start);
+		    	break;
+		    case 4:
+		    	start= insertend(start);
+		    	break;
+		    case 5:
+		    	start= insertbefore(start);
+		    	break;
+		    case 6:
+		    	start= insertafter(start);
+		    	break;
+		    case 7:
+		    	start= deletebeg(start);
+		    	break;
+		    case 8:
+		    	start= deleteend(start);
+		    	break;
+		    case 9:
+		    	start= deletenode(start);
+		    	break;
+		    case 10:
+		    	start= deleteafter(start);
+		    	break;
+		    case 11:
+		    	start=deletebefore(start);
+		    	break;
+		    case 12:
+		    	start= deletelist(start);
+		    	cout<<"\n linked list deleted";
+		    	break;
+		    case 13:
+		    	start= sortll(start);
+		    	break;
+		     
+		}
+	}while(option!=14);
+	
+	return 0;
+}
+
+node* createll(node *start)
+{
+	node* nn,*p;
+	int num;
+	cout<<"\nenter -1 to end\n";
+	cin>>num;
+	while(num!=-1)
+	{
+		nn=new node(num);
+		if(start==NULL)
+		{		
+		    start=nn;
+		}
+		else
+		{
+			p=start;
+			while(p->next!=NULL)
+				p=p->next;
+			p->next=nn;
+			nn->prev=p;
+		}
+		cin>>num;
+	}
+	return start;
+}
+node *display(node* start)
+{
+	node *t=start;
+	while(t!=NULL)
+	{
+		cout<<t->data<<" -> ";
+		t=t->next;
+	}
+	cout<<"NULL\n";
+	return start;
+}
+
+node *insertbeg(node *start)
+{
+    cin>>num;
+	node *nn= new node(num);
+	nn->next=start;
+	start=nn;
+	return start;
+}
+
+node *insertend(node *start)
+{
+	cin>>num;
+	node *nn=new node(num);
+	node *p=start;
+	while(p->next!=NULL)
+	{
+		p=p->next;
+	}
+	p->next=nn;
+	nn->prev=p;
+	
+	return start;	
+}
+node *insertbefore(node *start)
+{
+   cin>>num>>val;
+   node *n= new node(num);
+   node *p=start;
+   while(p->data!=val)
+   p=p->next;
+   n->prev=p->prev;
+   n->next=p;
+   p->prev->next=n;
+   p->prev=n;
+   return start;	
+}
+
+node *insertafter(node *start)
+{
+	cin>>num>>val;
+	node *nn=new node(num);
+	node *p= start;
+	while(p->data!=val)
+	{
+		p=p->next;
+	}
+    nn->next=p->next;
+    nn->prev=p;
+    p->next->prev=nn;
+    p->next=nn;
+
+return start;
+}
+
+node *deletebeg(node *start)
+{
+	node *nn;
+	nn= start;
+	start=nn->next;
+	start->prev=NULL;
+	free(nn);
+	
+	return start;
+}
+
+node *deleteend(node *start)
+{
+	node *nn=start;
+	while(nn->next!=NULL)
+	{
+		nn=nn->next;
+	}
+    nn->prev->next=NULL;
+    free(nn);
+	return start;
+}
+
+node *deletenode(node *start)
+{
+	cin>>val;
+	node *p=start;
+while(p->data!=val)
+{
+	p=p->next;
+}
+p->prev->next= p->next;
+free(p);
+
+return start;
+	
+}
+
+node *deleteafter(node *start)
+{
+	node *p=start,*t;
+	int num;
+	cin>>num;
+	while(p->data!=num)
+	{
+		p=p->next;
+	}
+	t=p->next;
+	p->next=t->next;
+	t->next->prev=p;
+	free(t);
+	return start;
+}
+node *deletebefore(node *start)
+{
+	node *p=start;
+	cin>>num;
+	while(p->data!=num)
+	p=p->next;
+	node *t=p->prev;
+	if(t==start)
+	start=deletebeg(start);
+	else{
+	p->prev=t->prev;
+	t->prev->next=p;
+}
+	free(t);
+	return start;
+}
+node *deletelist(node *start)
+{
+	node *n=start;
+	while(n!=NULL)
+	{
+		start= deletebeg(start);
+		n=start;
+	}
+	
+	return start;
+}
+
+node *sortll(node *start)
+{
+	node *p1,*p2;
+	int t;
+	p1=start;
+	while(p1->next!=NULL)
+	{
+		p2=p1->next;
+		while(p2!=NULL)
+		{
+			if(p1->data>p2->data)
+			{
+				t=p1->data;
+				p1->data=p2->data;
+				p2->data=t;
+			}
+			p2=p2->next;
+		}
+		p1=p1->next;
+	}
+	return start;
+}
diff --git a/04. circular linked list.cpp b/04. circular linked list.cpp
new file mode 100644
index 00000000..d00ced8a
--- /dev/null
+++ b/04. circular linked list.cpp	
@@ -0,0 +1,317 @@
+/*
+     hare krishna hare krishna krishna krishna hare hare
+     hare rama hare rama rama rama hare
+*/
+
+//// happy coding ////
+//// chant hare krishna /////
+//// ritik dagar ///////
+
+#include<bits/stdc++.h>
+using namespace std;
+
+class node{
+	public:
+		int data;
+		node *prev;
+		node *next;
+		node()
+		{
+			data=0;
+			prev=next=NULL;
+		}
+		node(int n)
+		{
+			data=n;
+			prev=NULL;
+			next=NULL;
+		}
+};
+int num,val;
+node *start = NULL;
+node *createll(node *);
+node *display(node *);
+node *insertbeg(node *);
+node *insertend(node *);
+node *insertbefore(node *);
+node *insertafter(node *);
+node *deletebeg(node *);
+node *deleteend(node *);
+node *deletenode(node *);
+node *deleteafter(node *);
+node *deletebefore(node *);
+node *deletelist(node *);
+node *sortll(node *);
+int main()
+{
+	int option;
+	cout<<"hare krishna hare krishna\nkrishna krishna hare hare\nhare rama hare rama\nrama rama hare hare\n";
+	cout<<"representation of circular doubly linked list\n";
+	do{
+		cout<<"\n\n *******MAIN MENU*******";
+		cout<<"\n 1:  Create a list ";
+		cout<<"\n 2:  Display the list ";
+		cout<<"\n 3:  Add a node at the begining";
+		cout<<"\n 4:  Add a node at the end";
+		cout<<"\n 5:  Add a node before a given node";
+		cout<<"\n 6:  Add a node after a given node";
+		cout<<"\n 7:  delete a node from the begining";
+		cout<<"\n 8:  delete a node from the end";
+		cout<<"\n 9:  delete a given node";
+		cout<<"\n 10: delete a node after given node";
+		cout<<"\n 11: delete a node before given node";
+		cout<<"\n 12: delete entire list";
+		cout<<"\n 13: sort the list";
+		cout<<"\n 14: exit\n";
+		cin>>option;
+		switch(option)
+		{
+			case 1:
+				start= createll(start);
+				cout<<"\n linked list created";
+				break;
+			case 2:
+				start= display(start);
+				break;
+		    case 3:
+		    	start= insertbeg(start);
+		    	break;
+		    case 4:
+		    	start= insertend(start);
+		    	break;
+		    case 5:
+		    	start= insertbefore(start);
+		    	break;
+		    case 6:
+		    	start= insertafter(start);
+		    	break;
+		    case 7:
+		    	start= deletebeg(start);
+		    	break;
+		    case 8:
+		    	start= deleteend(start);
+		    	break;
+		    case 9:
+		    	start= deletenode(start);
+		    	break;
+		    case 10:
+		    	start= deleteafter(start);
+		    	break;
+		    case 11:
+		    	start=deletebefore(start);
+		    	break;
+		    case 12:
+		    	start= deletelist(start);
+		    	cout<<"\n linked list deleted";
+		    	break;
+		    case 13:
+		    	start= sortll(start);
+		    	break;
+		     
+		}
+	}while(option!=14);
+	
+	return 0;
+}
+
+node* createll(node *start)
+{
+	node* nn,*p;
+	int num;
+	cout<<"\nenter -1 to end\n";
+	cin>>num;
+	while(num!=-1)
+	{
+		nn=new node(num);
+		if(start==NULL)
+		{		
+		    nn->next=start;
+		    start=nn;
+		}
+		else
+		{
+			p=start;
+			while(p->next!=start)
+				p=p->next;
+			p->next=nn;
+			nn->prev=p;
+			nn->next=start;
+			start->prev=nn;
+		}
+		cin>>num;
+	}
+	return start;
+}
+node *display(node* start)
+{
+	node *t=start;
+	while(t->next!=start)
+	{
+		cout<<t->data<<" -> ";
+		t=t->next;
+	}
+    cout<<t->data;
+	return start;
+}
+
+node *insertbeg(node *start)
+{
+    cin>>num;
+	node *nn= new node(num);
+	nn->next=start;
+	start->prev=nn;
+	start=nn;
+	return start;
+}
+
+node *insertend(node *start)
+{
+	cin>>num;
+	node *nn=new node(num);
+	node *p=start;
+	while(p->next!=start)
+	{
+		p=p->next;
+	}
+	p->next=nn;
+	nn->prev=p;
+	nn->next=start;
+	start->prev=nn;
+	
+	return start;	
+}
+node *insertbefore(node *start)
+{
+   cin>>num>>val;
+   node *n= new node(num);
+   node *p=start;
+   while(p->data!=val)
+   p=p->next;
+   n->prev=p->prev;
+   n->next=p;
+   p->prev->next=n;
+   p->prev=n;
+   return start;	
+}
+
+node *insertafter(node *start)
+{
+	cin>>num>>val;
+	node *nn=new node(num);
+	node *p= start;
+	while(p->data!=val)
+	{
+		p=p->next;
+	}
+    nn->next=p->next;
+    nn->prev=p;
+    p->next->prev=nn;
+    p->next=nn;
+
+return start;
+}
+
+node *deletebeg(node *start)
+{
+	node *nn;
+	nn= start;
+	start=nn->next;
+	start->prev=NULL;
+	free(nn);
+	
+	return start;
+}
+
+node *deleteend(node *start)
+{
+	node *nn=start;
+	while(nn->next!=start)
+	{
+		nn=nn->next;
+	}
+    nn->prev->next=start;
+    free(nn);
+	return start;
+}
+
+node *deletenode(node *start)
+{
+	cin>>val;
+	node *p=start;
+while(p->data!=val)
+{
+	p=p->next;
+}
+p->prev->next= p->next;
+p->next->prev=p->prev;
+free(p);
+
+return start;
+	
+}
+
+node *deleteafter(node *start)
+{
+	node *p=start,*t;
+	int num;
+	cin>>num;
+	while(p->data!=num)
+	{
+		p=p->next;
+	}
+	t=p->next;
+	p->next=t->next;
+	t->next->prev=p;
+	free(t);
+	return start;
+}
+node *deletebefore(node *start)
+{
+	node *p=start;
+	cin>>num;
+	while(p->data!=num)
+	p=p->next;
+	node *t=p->prev;
+	if(t==start)
+	start=deletebeg(start);
+	else{
+	p->prev=t->prev;
+	t->prev->next=p;
+}
+	free(t);
+	return start;
+}
+node *deletelist(node *start)
+{
+	node *n=start;
+	while(n->next!=NULL)
+	{
+		start= deleteend(start);
+	}
+	free(start);
+	return start;
+}
+
+node *sortll(node *start)
+{
+	node *p1,*p2;
+	int t;
+	p1=start;
+	while(p1->next!=NULL)
+	{
+		p2=p1->next;
+		while(p2!=NULL)
+		{
+			if(p1->data>p2->data)
+			{
+				t=p1->data;
+				p1->data=p2->data;
+				p2->data=t;
+			}
+			p2=p2->next;
+		}
+		p1=p1->next;
+	}
+	return start;
+}
+
diff --git a/05. header linked list.cpp b/05. header linked list.cpp
new file mode 100644
index 00000000..8a5d9c21
--- /dev/null
+++ b/05. header linked list.cpp	
@@ -0,0 +1,93 @@
+/*
+     hare krishna hare krishna krishna krishna hare hare
+     hare rama hare rama rama rama hare
+*/
+
+//// happy coding ////
+//// chant hare krishna /////
+//// rk dagar ///////
+
+#include<bits/stdc++.h>
+using namespace std;
+
+class node{
+	public:
+		int data;
+		node *next;
+		node(int n)
+		{
+			data=n;
+			next=NULL;
+		}
+			node()
+		{
+			data=0;
+			next=NULL;
+		}
+};
+
+node *start = NULL;
+node *createll(node *);
+node *display(node *);
+int main()
+{
+	int option;
+	do{
+		cout<<"\n\n *******MAIN MENU*******";
+		cout<<"\n 1:  Create a header linked list ";
+		cout<<"\n 2:  Display the header linked list ";
+		cout<<"\n 3:  exit\n";
+		cin>>option;
+		switch(option)
+		{
+			case 1:
+				start= createll(start);
+				cout<<"\nheader linked list created";
+				break;
+			case 2:
+				start= display(start);
+				break;
+
+		}
+	}while(option!=3);
+	
+	return 0;
+}
+
+node* createll(node *start)
+{
+	node* n,*p;
+	int num;
+	cout<<"\nenter -1 to end\n";
+	cin>>num;
+	while(num!=-1)
+	{
+		n=new node(num);
+		if(start==NULL)
+		{		
+		    start = new node();
+		    start->next=n;
+		}
+		else
+		{
+			p=start;
+			while(p->next!=NULL)
+				p=p->next;
+			p->next=n;
+		}
+		cin>>num;
+	}
+	return start;
+}
+node *display(node* start)
+{
+	node *t=start;
+	while(t!=NULL)
+	{
+		cout<<t->data<<" -> ";
+		t=t->next;
+	}
+	cout<<"NULL\n";
+	return start;
+}
+
diff --git a/06. Addition and Subtraction on two polynomials.cpp b/06. Addition and Subtraction on two polynomials.cpp
new file mode 100644
index 00000000..c6f0639c
--- /dev/null
+++ b/06. Addition and Subtraction on two polynomials.cpp	
@@ -0,0 +1,215 @@
+/*
+     hare krishna hare krishna krishna krishna hare hare
+     hare rama hare rama rama rama hare
+*/
+#include<bits/stdc++.h>
+using namespace std;
+int n,c,num,val;
+class node{
+	public:
+		int num,coeff;
+		node *next;
+		node(int n,int c)
+		{
+			num=n;
+			coeff=c;
+			next=NULL;
+		}
+		node()
+		{
+			num=0,coeff=0;
+			next=NULL;
+		}
+};
+
+node *start1 = NULL,*start2=NULL,*start3=NULL,*start4=NULL;
+
+
+node* createll(node *start)
+{
+	node* n,*p;
+	cout<<"\nenter -1 to end\n";
+	cin>>num>>c;
+	while(num!=-1)
+	{
+		n=new node(num,c);
+		if(start==NULL)
+		{	
+		    start=n;
+		}
+		else
+		{
+			p=start;
+			while(p->next!=NULL)
+				p=p->next;
+			p->next=n;
+		}
+		cin>>num;
+		if(num==-1)
+		break;
+		cin>>c;
+	}
+	return start;
+}
+node *display(node* start)
+{
+	node *t=start;
+	while(t!=NULL)
+	{
+		cout<<t->num<<" x ^ "<<t->coeff<<" -> ";
+		t=t->next;
+	}
+	cout<<"NULL\n";
+	return start;
+}
+node *addnode(node *start,int num,int c)
+{
+	node *p,*n;
+	n=new node(num,c);
+	if(start==NULL)
+	{
+		start=n;
+	}
+	else
+	{
+		p=start;
+		while(p->next!=NULL)
+		p=p->next;
+		p->next=n;
+	}
+	return start;
+}
+node *addpoly(node *start3,node* a,node *b)
+{
+	node *p1=a,*p2=b;
+	int sum;
+	while(p1!=NULL&&p2!=NULL)
+	{
+		if(p1->coeff==p2->coeff)
+		{
+			sum= p1->num+p2->num;
+			start3 = addnode(start3,sum,p1->coeff);
+			p1=p1->next;
+			p2=p2->next;
+		}
+		else if(p1->coeff>p2->coeff)
+		{
+			start3= addnode(start3,p1->num,p1->coeff);
+			p1=p1->next;
+		}
+		else if(p2->coeff>p1->coeff)
+		{
+			start3= addnode(start3,p2->num,p2->coeff);
+			p2=p2->next;
+		}		
+	}
+	if(p1==NULL)
+	{
+		while(p2!=NULL)
+		{
+			start3= addnode(start3,p2->num,p2->coeff);
+			p2=p2->next;
+		}
+	}
+	if(p2==NULL)
+	{
+		while(p1!=NULL)
+		{
+			start3= addnode(start3,p1->num,p1->coeff);
+			p1=p1->next;
+		}
+	}
+	return start3;
+}
+node *subpoly(node *s4,node *a,node *b)
+{
+    int diff;
+	node *p1=a, *p2=b;
+	while(p1!=NULL&&p2!=NULL)
+	{
+		if(p1->coeff==p2->coeff)
+		{
+			diff= p1->num - p2->num;
+			s4= addnode(s4,diff,p1->coeff);
+			p1=p1->next;
+			p2=p2->next;
+		}
+		else if(p1->coeff>p2->coeff)
+		{
+			s4= addnode(s4,p1->num,p1->coeff);
+			p1=p1->next;
+		}
+		else if(p2->coeff>p1->coeff)
+		{
+			s4= addnode(s4,p2->num,p2->coeff);
+			p2=p2->next;
+		}
+	}
+	if(p1==NULL)
+	{
+		while(p2!=NULL)
+		{
+				s4= addnode(s4,p2->num,p2->coeff);
+			p2=p2->next;
+			
+		}
+	}
+	if(p2==NULL)
+	{
+		while(p1!=NULL)
+		{
+				s4= addnode(s4,p1->num,p1->coeff);
+			p1=p1->next;
+		}
+	}
+	
+	return s4;
+}
+int main()
+{
+	int option;
+	do{
+		cout<<"\n\n *******MAIN MENU*******";
+		cout<<"\n 1:  Enter First Polynomial ";
+		cout<<"\n 2:  Display First Polynomial ";
+		cout<<"\n 3:  Enter Second Polynomial";
+		cout<<"\n 4:  Display Second Polynomial";
+		cout<<"\n 5:  Add the Polynomials";
+		cout<<"\n 6:  Display the add result Polynomial";
+		cout<<"\n 7:  Subtract the polynomials";
+		cout<<"\n 8:  Display the subtract result polynomial";
+		cout<<"\n 9:  exit\n";
+		cin>>option;
+		switch(option)
+		{
+			case 1:
+				start1= createll(start1);
+				break;
+			case 2:
+				display(start1);
+				break;
+			case 3:
+				start2= createll(start2);
+				break;
+			case 4:
+				display(start2);
+				break;
+			case 5:
+				start3= addpoly(start3,start1,start2);
+				break;
+			case 6:
+				display(start3);
+				break;
+			case 7:
+				start4= subpoly(start4,start1,start2);
+				break;
+			case 8:
+				display(start4);
+				break;
+
+    	}
+	}while(option!=9);
+	
+	return 0;
+}
+
diff --git a/Linked List Algo/01. singlylinkedlist.cpp b/Linked List Algo/01. singlylinkedlist.cpp
new file mode 100644
index 00000000..2bd4196d
--- /dev/null
+++ b/Linked List Algo/01. singlylinkedlist.cpp	
@@ -0,0 +1,298 @@
+
+//// happy coding ////
+//// chant hare krishna /////
+//// rk dagar ///////
+
+#include<bits/stdc++.h>
+using namespace std;
+
+class node{
+	public:
+		int data;
+		node *next;
+};
+
+node *start = NULL;
+node *createll(node *);
+node *display(node *);
+node *insertbeg(node *);
+node *insertend(node *);
+node *insertbefore(node *);
+node *insertafter(node *);
+node *deletebeg(node *);
+node *deleteend(node *);
+node *deletenode(node *);
+node *deleteafter(node *);
+node *deletelist(node *);
+node *sortll(node *);
+int main()
+{
+	int option;
+	do{
+		cout<<"\n\n *******MAIN MENU*******";
+		cout<<"\n 1:  Create a list ";
+		cout<<"\n 2:  Display the list ";
+		cout<<"\n 3:  Add a node at the begining";
+		cout<<"\n 4:  Add a node at the end";
+		cout<<"\n 5:  Add a node before a given node";
+		cout<<"\n 6:  Add a node after a given node";
+		cout<<"\n 7:  delete a node from the begining";
+		cout<<"\n 8:  delete a node from the end";
+		cout<<"\n 9:  delete a given node";
+		cout<<"\n 10: delete a node after given node";
+		cout<<"\n 11: delete entire list";
+		cout<<"\n 12: sort the list";
+		cout<<"\n 13: exit\n";
+		cin>>option;
+		switch(option)
+		{
+			case 1:
+				start= createll(start);
+				cout<<"\n linked list created";
+				break;
+			case 2:
+				start= display(start);
+				break;
+		    case 3:
+		    	start= insertbeg(start);
+		    	break;
+		    case 4:
+		    	start= insertend(start);
+		    	break;
+		    case 5:
+		    	start= insertbefore(start);
+		    	break;
+		    case 6:
+		    	start= insertafter(start);
+		    	break;
+		    case 7:
+		    	start= deletebeg(start);
+		    	break;
+		    case 8:
+		    	start= deleteend(start);
+		    	break;
+		    case 9:
+		    	start= deletenode(start);
+		    	break;
+		    case 10:
+		    	start= deleteafter(start);
+		    	break;
+		    case 11:
+		    	start= deletelist(start);
+		    	cout<<"\n linked list deleted";
+		    	break;
+		    case 12:
+		    	start= sortll(start);
+		    	break;
+		     
+		}
+	}while(option!=13);
+	
+	return 0;
+}
+
+node* createll(node *start)
+{
+	node* nn,*p;
+	int num;
+	cout<<"\nenter -1 to end\n";
+	cin>>num;
+	while(num!=-1)
+	{
+		nn=new node();
+		nn->data=num;
+		nn->next=NULL;
+		if(start==NULL)
+		{		
+		    start=nn;
+		}
+		else
+		{
+			p=start;
+			while(p->next!=NULL)
+				p=p->next;
+			p->next=nn;
+		}
+		cin>>num;
+	}
+	return start;
+}
+node *display(node* start)
+{
+	node *t=start;
+	while(t!=NULL)
+	{
+		cout<<t->data<<" -> ";
+		t=t->next;
+	}
+	cout<<"NULL\n";
+	return start;
+}
+
+node *insertbeg(node *start)
+{
+	node *nn= new node();
+	int num;
+	cin>>num;
+	nn->data=num;
+	nn->next=start;
+	start=nn;
+	
+	return start;
+}
+
+node *insertend(node *start)
+{
+	node *nn=new node();
+	node *p=start;
+	int num;
+	cin>>num;
+	nn->data=num;
+	nn->next=NULL;
+	while(p->next!=NULL)
+	{
+		p=p->next;
+	}
+	p->next=nn;
+	
+	
+	return start;
+	
+	
+}
+node *insertbefore(node *start)
+{
+	node *nn= new node();
+	node *p=start;
+	node *preptr;
+	int num,val;
+	cin>>num>>val;
+	nn->data=num;
+	while(p->data!=val)
+	{
+		preptr=p;
+		p=p->next;
+	}
+	preptr->next=nn;
+	nn->next=p;
+	
+	return start;
+	
+}
+
+node *insertafter(node *start)
+{
+	node *nn=new node();
+	node *p= start,*pre=start;
+	int num,val;
+	cin>>num>>val;
+	nn->data=num;
+	while(pre->data!=val)
+	{
+		pre= p;
+		p=p->next;
+	}
+nn->next=p;
+pre->next=nn;
+
+return start;
+}
+
+node *deletebeg(node *start)
+{
+	node *nn;
+	nn= start;
+	start=nn->next;
+	free(nn);
+	
+	return start;
+}
+
+node *deleteend(node *start)
+{
+	node *nn=start,*p;
+	while(nn->next!=NULL)
+	{
+		p=nn;
+		nn=nn->next;
+	}
+	p->next=NULL;
+	free(nn);
+	
+	return start;
+}
+
+node *deletenode(node *start)
+{
+	int val;
+	cin>>val;
+	node *p=start,*pre;
+	while(p->data==val) 
+	{
+		start= deletebeg(start);
+	return start;
+}
+while(p->data!=val)
+{
+	pre=p;
+	p=p->next;
+}
+pre->next=p->next;
+free(p);
+
+return start;
+	
+}
+
+node *deleteafter(node *start)
+{
+	node *nn,*p=start;
+	nn=start;
+	int num;
+	cin>>num;
+	while(p->data!=num)
+	{
+		p=nn;
+		nn=nn->next;
+	}
+	p->next=nn->next;
+	free(nn);
+	
+	return start;
+}
+
+node *deletelist(node *start)
+{
+	node *n=start;
+	while(n!=NULL)
+	{
+		start= deletebeg(start);
+		n=start;
+	}
+	
+	return start;
+}
+
+node *sortll(node *start)
+{
+	node *p1,*p2;
+	int t;
+	p1=start;
+	while(p1->next!=NULL)
+	{
+		p2=p1->next;
+		while(p2!=NULL)
+		{
+			if(p1->data>p2->data)
+			{
+				t=p1->data;
+				p1->data=p2->data;
+				p2->data=t;
+			}
+			p2=p2->next;
+		}
+		p1=p1->next;
+	}
+	return start;
+}
+
diff --git a/Linked List Algo/02. circular singly linked list.cpp b/Linked List Algo/02. circular singly linked list.cpp
new file mode 100644
index 00000000..087b8b82
--- /dev/null
+++ b/Linked List Algo/02. circular singly linked list.cpp	
@@ -0,0 +1,314 @@
+/*
+     hare krishna hare krishna krishna krishna hare hare
+     hare rama hare rama rama rama hare
+*/
+
+//// happy coding ////
+//// chant hare krishna /////
+//// ritik dagar ///////
+
+#include<bits/stdc++.h>
+using namespace std;
+
+class node{
+	public:
+		int data;
+		node *next;
+};
+
+node *start = NULL;
+node *createll(node *);
+node *display(node *);
+node *insertbeg(node *);
+node *insertend(node *);
+node *insertbefore(node *);
+node *insertafter(node *);
+node *deletebeg(node *);
+node *deleteend(node *);
+node *deletenode(node *);
+node *deleteafter(node *);
+node *deletelist(node *);
+node *sortll(node *);
+int main()
+{
+	int option;
+	cout<<"hare krishna hare krishna\nkrishna krishna hare hare\nhare rama hare rama\nrama rama hare hare\n";
+	cout<<"implementation of circular linked list\n";
+	do{
+		cout<<"\n\n *******MAIN MENU*******";
+		cout<<"\n 1:  Create a list ";
+		cout<<"\n 2:  Display the list ";
+		cout<<"\n 3:  Add a node at the begining";
+		cout<<"\n 4:  Add a node at the end";
+		cout<<"\n 5:  Add a node before a given node";
+		cout<<"\n 6:  Add a node after a given node";
+		cout<<"\n 7:  delete a node from the begining";
+		cout<<"\n 8:  delete a node from the end";
+		cout<<"\n 9:  delete a given node";
+		cout<<"\n 10: delete a node after given node";
+		cout<<"\n 11: delete entire list";
+		cout<<"\n 12: sort the list";
+		cout<<"\n 13: exit\n";
+		cin>>option;
+		switch(option)
+		{
+			case 1:
+				start= createll(start);
+				cout<<"\ncircular linked list created";
+				break;
+			case 2:
+				start= display(start);
+				break;
+		    case 3:
+		    	start= insertbeg(start);
+		    	break;
+		    case 4:
+		    	start= insertend(start);
+		    	break;
+		    case 5:
+		    	start= insertbefore(start);
+		    	break;
+		    case 6:
+		    	start= insertafter(start);
+		    	break;
+		    case 7:
+		    	start= deletebeg(start);
+		    	break;
+		    case 8:
+		    	start= deleteend(start);
+		    	break;
+		    case 9:
+		    	start= deletenode(start);
+		    	break;
+		    case 10:
+		    	start= deleteafter(start);
+		    	break;
+		    case 11:
+		    	start= deletelist(start);
+		    	cout<<"\ncircular linked list deleted";
+		    	break;
+		    case 12:
+		    	start= sortll(start);
+		    	break;
+		     
+		}
+	}while(option!=13);
+	
+	return 0;
+}
+
+node* createll(node *start)
+{
+	node* nn,*p;
+	int num;
+	cout<<"\nenter -1 to end\n";
+	cin>>num;
+	while(num!=-1)
+	{
+		nn=new node();
+		nn->data=num;
+		if(start==NULL)
+		{
+		    nn->next=nn;	
+		    start=nn;
+		}
+		else
+		{
+			p=start;
+			while(p->next!=start)
+				p=p->next;
+			p->next=nn;
+			nn->next=start;
+		}
+		cin>>num;
+	}
+	return start;
+}
+node *display(node* start)
+{
+	node *t=start;
+	while(t->next!=start)
+	{
+		cout<<t->data<<" -> ";
+		t=t->next;
+	}
+	cout<<t->data<<"\n";
+	return start;
+}
+
+node *insertbeg(node *start)
+{
+	node *p,*nn= new node();
+	int num;
+	cin>>num;
+	p=start;
+	while(p->next!=start)
+	p=p->next;
+	p->next=nn;
+	nn->data=num;
+	nn->next=start;
+	start=nn;
+	
+	return start;
+}
+
+node *insertend(node *start)
+{
+	node *nn=new node();
+	node *p=start;
+	int num;
+	cin>>num;
+	nn->data=num;
+	nn->next=start;
+	while(p->next!=start)
+	{
+		p=p->next;
+	}
+	p->next=nn;
+	
+	
+	return start;
+	
+	
+}
+node *insertbefore(node *start)
+{
+	node *nn= new node();
+	node *p=start;
+	node *preptr;
+	int num,val;
+	cin>>num>>val;
+	nn->data=num;
+	while(p->data!=val)
+	{
+		preptr=p;
+		p=p->next;
+	}
+	preptr->next=nn;
+	nn->next=p;
+	
+	return start;
+	
+}
+
+node *insertafter(node *start)
+{
+	node *nn=new node();
+	node *p= start,*pre=start;
+	int num,val;
+	cin>>num>>val;
+	nn->data=num;
+	while(pre->data!=val)
+	{
+		pre= p;
+		p=p->next;
+	}
+nn->next=p;
+pre->next=nn;
+
+return start;
+}
+
+node *deletebeg(node *start)
+{
+	node *nn;
+	nn= start;
+	while(nn->next!=start)
+	nn= nn->next; 
+	nn->next=start->next;
+	free(start);
+	start=nn->next;
+	
+	
+	return start;
+}
+
+node *deleteend(node *start)
+{
+	node *nn=start,*p;
+	while(nn->next!=start)
+	{
+		p=nn;
+		nn=nn->next;
+	}
+	p->next=nn->next;
+	free(nn);
+	
+	return start;
+}
+
+node *deletenode(node *start)
+{
+	int val;
+	cin>>val;
+	node *p=start,*pre;
+	while(p->data==val) 
+	{
+		start= deletebeg(start);
+	return start;
+}
+while(p->data!=val)
+{
+	pre=p;
+	p=p->next;
+}
+pre->next=p->next;
+free(p);
+
+return start;
+	
+}
+
+node *deleteafter(node *start)
+{
+	node *nn,*p;
+	nn=start;
+	p=nn;
+	int num;
+	cin>>num;
+	while(p->data!=num)
+	{
+		p=nn;
+		nn=nn->next;
+	}
+	p->next=nn->next;
+	if(nn==start)
+	start=p->next;
+	free(nn);
+	
+	return start;
+}
+
+node *deletelist(node *start)
+{
+	node *n=start;
+	while(n->next!=start)
+	{
+		start= deleteend(start);
+	}
+	free(start);
+	return start;
+}
+
+node *sortll(node *start)
+{
+	node *p1,*p2;
+	int t;
+	p1=start;
+	while(p1->next!=start)
+	{
+		p2=p1->next;
+		while(p2!=start)
+		{
+			if(p1->data>p2->data)
+			{
+				t=p1->data;
+				p1->data=p2->data;
+				p2->data=t;
+			}
+			p2=p2->next;
+		}
+		p1=p1->next;
+	}
+	return start;
+}
diff --git a/Linked List Algo/03. doubly linked list.cpp b/Linked List Algo/03. doubly linked list.cpp
new file mode 100644
index 00000000..d4501d08
--- /dev/null
+++ b/Linked List Algo/03. doubly linked list.cpp	
@@ -0,0 +1,310 @@
+/*
+     hare krishna hare krishna krishna krishna hare hare
+     hare rama hare rama rama rama hare
+*/
+
+//// happy coding ////
+//// chant hare krishna /////
+//// ritik dagar ///////
+
+#include<bits/stdc++.h>
+using namespace std;
+
+class node{
+	public:
+		int data;
+		node *prev;
+		node *next;
+		node()
+		{
+			data=0;
+			prev=next=NULL;
+		}
+		node(int n)
+		{
+			data=n;
+			prev=NULL;
+			next=NULL;
+		}
+};
+int num,val;
+node *start = NULL;
+node *createll(node *);
+node *display(node *);
+node *insertbeg(node *);
+node *insertend(node *);
+node *insertbefore(node *);
+node *insertafter(node *);
+node *deletebeg(node *);
+node *deleteend(node *);
+node *deletenode(node *);
+node *deleteafter(node *);
+node *deletebefore(node *);
+node *deletelist(node *);
+node *sortll(node *);
+int main()
+{
+	int option;
+	cout<<"hare krishna hare krishna\nkrishna krishna hare hare\nhare rama hare rama\nrama rama hare hare\n";
+	cout<<"representation of doubly linked list\n";
+	do{
+		cout<<"\n\n *******MAIN MENU*******";
+		cout<<"\n 1:  Create a list ";
+		cout<<"\n 2:  Display the list ";
+		cout<<"\n 3:  Add a node at the begining";
+		cout<<"\n 4:  Add a node at the end";
+		cout<<"\n 5:  Add a node before a given node";
+		cout<<"\n 6:  Add a node after a given node";
+		cout<<"\n 7:  delete a node from the begining";
+		cout<<"\n 8:  delete a node from the end";
+		cout<<"\n 9:  delete a given node";
+		cout<<"\n 10: delete a node after given node";
+		cout<<"\n 11: delete a node before given node";
+		cout<<"\n 12: delete entire list";
+		cout<<"\n 13: sort the list";
+		cout<<"\n 14: exit\n";
+		cin>>option;
+		switch(option)
+		{
+			case 1:
+				start= createll(start);
+				cout<<"\n linked list created";
+				break;
+			case 2:
+				start= display(start);
+				break;
+		    case 3:
+		    	start= insertbeg(start);
+		    	break;
+		    case 4:
+		    	start= insertend(start);
+		    	break;
+		    case 5:
+		    	start= insertbefore(start);
+		    	break;
+		    case 6:
+		    	start= insertafter(start);
+		    	break;
+		    case 7:
+		    	start= deletebeg(start);
+		    	break;
+		    case 8:
+		    	start= deleteend(start);
+		    	break;
+		    case 9:
+		    	start= deletenode(start);
+		    	break;
+		    case 10:
+		    	start= deleteafter(start);
+		    	break;
+		    case 11:
+		    	start=deletebefore(start);
+		    	break;
+		    case 12:
+		    	start= deletelist(start);
+		    	cout<<"\n linked list deleted";
+		    	break;
+		    case 13:
+		    	start= sortll(start);
+		    	break;
+		     
+		}
+	}while(option!=14);
+	
+	return 0;
+}
+
+node* createll(node *start)
+{
+	node* nn,*p;
+	int num;
+	cout<<"\nenter -1 to end\n";
+	cin>>num;
+	while(num!=-1)
+	{
+		nn=new node(num);
+		if(start==NULL)
+		{		
+		    start=nn;
+		}
+		else
+		{
+			p=start;
+			while(p->next!=NULL)
+				p=p->next;
+			p->next=nn;
+			nn->prev=p;
+		}
+		cin>>num;
+	}
+	return start;
+}
+node *display(node* start)
+{
+	node *t=start;
+	while(t!=NULL)
+	{
+		cout<<t->data<<" -> ";
+		t=t->next;
+	}
+	cout<<"NULL\n";
+	return start;
+}
+
+node *insertbeg(node *start)
+{
+    cin>>num;
+	node *nn= new node(num);
+	nn->next=start;
+	start=nn;
+	return start;
+}
+
+node *insertend(node *start)
+{
+	cin>>num;
+	node *nn=new node(num);
+	node *p=start;
+	while(p->next!=NULL)
+	{
+		p=p->next;
+	}
+	p->next=nn;
+	nn->prev=p;
+	
+	return start;	
+}
+node *insertbefore(node *start)
+{
+   cin>>num>>val;
+   node *n= new node(num);
+   node *p=start;
+   while(p->data!=val)
+   p=p->next;
+   n->prev=p->prev;
+   n->next=p;
+   p->prev->next=n;
+   p->prev=n;
+   return start;	
+}
+
+node *insertafter(node *start)
+{
+	cin>>num>>val;
+	node *nn=new node(num);
+	node *p= start;
+	while(p->data!=val)
+	{
+		p=p->next;
+	}
+    nn->next=p->next;
+    nn->prev=p;
+    p->next->prev=nn;
+    p->next=nn;
+
+return start;
+}
+
+node *deletebeg(node *start)
+{
+	node *nn;
+	nn= start;
+	start=nn->next;
+	start->prev=NULL;
+	free(nn);
+	
+	return start;
+}
+
+node *deleteend(node *start)
+{
+	node *nn=start;
+	while(nn->next!=NULL)
+	{
+		nn=nn->next;
+	}
+    nn->prev->next=NULL;
+    free(nn);
+	return start;
+}
+
+node *deletenode(node *start)
+{
+	cin>>val;
+	node *p=start;
+while(p->data!=val)
+{
+	p=p->next;
+}
+p->prev->next= p->next;
+free(p);
+
+return start;
+	
+}
+
+node *deleteafter(node *start)
+{
+	node *p=start,*t;
+	int num;
+	cin>>num;
+	while(p->data!=num)
+	{
+		p=p->next;
+	}
+	t=p->next;
+	p->next=t->next;
+	t->next->prev=p;
+	free(t);
+	return start;
+}
+node *deletebefore(node *start)
+{
+	node *p=start;
+	cin>>num;
+	while(p->data!=num)
+	p=p->next;
+	node *t=p->prev;
+	if(t==start)
+	start=deletebeg(start);
+	else{
+	p->prev=t->prev;
+	t->prev->next=p;
+}
+	free(t);
+	return start;
+}
+node *deletelist(node *start)
+{
+	node *n=start;
+	while(n!=NULL)
+	{
+		start= deletebeg(start);
+		n=start;
+	}
+	
+	return start;
+}
+
+node *sortll(node *start)
+{
+	node *p1,*p2;
+	int t;
+	p1=start;
+	while(p1->next!=NULL)
+	{
+		p2=p1->next;
+		while(p2!=NULL)
+		{
+			if(p1->data>p2->data)
+			{
+				t=p1->data;
+				p1->data=p2->data;
+				p2->data=t;
+			}
+			p2=p2->next;
+		}
+		p1=p1->next;
+	}
+	return start;
+}
diff --git a/Linked List Algo/04. circular linked list.cpp b/Linked List Algo/04. circular linked list.cpp
new file mode 100644
index 00000000..d00ced8a
--- /dev/null
+++ b/Linked List Algo/04. circular linked list.cpp	
@@ -0,0 +1,317 @@
+/*
+     hare krishna hare krishna krishna krishna hare hare
+     hare rama hare rama rama rama hare
+*/
+
+//// happy coding ////
+//// chant hare krishna /////
+//// ritik dagar ///////
+
+#include<bits/stdc++.h>
+using namespace std;
+
+class node{
+	public:
+		int data;
+		node *prev;
+		node *next;
+		node()
+		{
+			data=0;
+			prev=next=NULL;
+		}
+		node(int n)
+		{
+			data=n;
+			prev=NULL;
+			next=NULL;
+		}
+};
+int num,val;
+node *start = NULL;
+node *createll(node *);
+node *display(node *);
+node *insertbeg(node *);
+node *insertend(node *);
+node *insertbefore(node *);
+node *insertafter(node *);
+node *deletebeg(node *);
+node *deleteend(node *);
+node *deletenode(node *);
+node *deleteafter(node *);
+node *deletebefore(node *);
+node *deletelist(node *);
+node *sortll(node *);
+int main()
+{
+	int option;
+	cout<<"hare krishna hare krishna\nkrishna krishna hare hare\nhare rama hare rama\nrama rama hare hare\n";
+	cout<<"representation of circular doubly linked list\n";
+	do{
+		cout<<"\n\n *******MAIN MENU*******";
+		cout<<"\n 1:  Create a list ";
+		cout<<"\n 2:  Display the list ";
+		cout<<"\n 3:  Add a node at the begining";
+		cout<<"\n 4:  Add a node at the end";
+		cout<<"\n 5:  Add a node before a given node";
+		cout<<"\n 6:  Add a node after a given node";
+		cout<<"\n 7:  delete a node from the begining";
+		cout<<"\n 8:  delete a node from the end";
+		cout<<"\n 9:  delete a given node";
+		cout<<"\n 10: delete a node after given node";
+		cout<<"\n 11: delete a node before given node";
+		cout<<"\n 12: delete entire list";
+		cout<<"\n 13: sort the list";
+		cout<<"\n 14: exit\n";
+		cin>>option;
+		switch(option)
+		{
+			case 1:
+				start= createll(start);
+				cout<<"\n linked list created";
+				break;
+			case 2:
+				start= display(start);
+				break;
+		    case 3:
+		    	start= insertbeg(start);
+		    	break;
+		    case 4:
+		    	start= insertend(start);
+		    	break;
+		    case 5:
+		    	start= insertbefore(start);
+		    	break;
+		    case 6:
+		    	start= insertafter(start);
+		    	break;
+		    case 7:
+		    	start= deletebeg(start);
+		    	break;
+		    case 8:
+		    	start= deleteend(start);
+		    	break;
+		    case 9:
+		    	start= deletenode(start);
+		    	break;
+		    case 10:
+		    	start= deleteafter(start);
+		    	break;
+		    case 11:
+		    	start=deletebefore(start);
+		    	break;
+		    case 12:
+		    	start= deletelist(start);
+		    	cout<<"\n linked list deleted";
+		    	break;
+		    case 13:
+		    	start= sortll(start);
+		    	break;
+		     
+		}
+	}while(option!=14);
+	
+	return 0;
+}
+
+node* createll(node *start)
+{
+	node* nn,*p;
+	int num;
+	cout<<"\nenter -1 to end\n";
+	cin>>num;
+	while(num!=-1)
+	{
+		nn=new node(num);
+		if(start==NULL)
+		{		
+		    nn->next=start;
+		    start=nn;
+		}
+		else
+		{
+			p=start;
+			while(p->next!=start)
+				p=p->next;
+			p->next=nn;
+			nn->prev=p;
+			nn->next=start;
+			start->prev=nn;
+		}
+		cin>>num;
+	}
+	return start;
+}
+node *display(node* start)
+{
+	node *t=start;
+	while(t->next!=start)
+	{
+		cout<<t->data<<" -> ";
+		t=t->next;
+	}
+    cout<<t->data;
+	return start;
+}
+
+node *insertbeg(node *start)
+{
+    cin>>num;
+	node *nn= new node(num);
+	nn->next=start;
+	start->prev=nn;
+	start=nn;
+	return start;
+}
+
+node *insertend(node *start)
+{
+	cin>>num;
+	node *nn=new node(num);
+	node *p=start;
+	while(p->next!=start)
+	{
+		p=p->next;
+	}
+	p->next=nn;
+	nn->prev=p;
+	nn->next=start;
+	start->prev=nn;
+	
+	return start;	
+}
+node *insertbefore(node *start)
+{
+   cin>>num>>val;
+   node *n= new node(num);
+   node *p=start;
+   while(p->data!=val)
+   p=p->next;
+   n->prev=p->prev;
+   n->next=p;
+   p->prev->next=n;
+   p->prev=n;
+   return start;	
+}
+
+node *insertafter(node *start)
+{
+	cin>>num>>val;
+	node *nn=new node(num);
+	node *p= start;
+	while(p->data!=val)
+	{
+		p=p->next;
+	}
+    nn->next=p->next;
+    nn->prev=p;
+    p->next->prev=nn;
+    p->next=nn;
+
+return start;
+}
+
+node *deletebeg(node *start)
+{
+	node *nn;
+	nn= start;
+	start=nn->next;
+	start->prev=NULL;
+	free(nn);
+	
+	return start;
+}
+
+node *deleteend(node *start)
+{
+	node *nn=start;
+	while(nn->next!=start)
+	{
+		nn=nn->next;
+	}
+    nn->prev->next=start;
+    free(nn);
+	return start;
+}
+
+node *deletenode(node *start)
+{
+	cin>>val;
+	node *p=start;
+while(p->data!=val)
+{
+	p=p->next;
+}
+p->prev->next= p->next;
+p->next->prev=p->prev;
+free(p);
+
+return start;
+	
+}
+
+node *deleteafter(node *start)
+{
+	node *p=start,*t;
+	int num;
+	cin>>num;
+	while(p->data!=num)
+	{
+		p=p->next;
+	}
+	t=p->next;
+	p->next=t->next;
+	t->next->prev=p;
+	free(t);
+	return start;
+}
+node *deletebefore(node *start)
+{
+	node *p=start;
+	cin>>num;
+	while(p->data!=num)
+	p=p->next;
+	node *t=p->prev;
+	if(t==start)
+	start=deletebeg(start);
+	else{
+	p->prev=t->prev;
+	t->prev->next=p;
+}
+	free(t);
+	return start;
+}
+node *deletelist(node *start)
+{
+	node *n=start;
+	while(n->next!=NULL)
+	{
+		start= deleteend(start);
+	}
+	free(start);
+	return start;
+}
+
+node *sortll(node *start)
+{
+	node *p1,*p2;
+	int t;
+	p1=start;
+	while(p1->next!=NULL)
+	{
+		p2=p1->next;
+		while(p2!=NULL)
+		{
+			if(p1->data>p2->data)
+			{
+				t=p1->data;
+				p1->data=p2->data;
+				p2->data=t;
+			}
+			p2=p2->next;
+		}
+		p1=p1->next;
+	}
+	return start;
+}
+
diff --git a/Linked List Algo/05. header linked list.cpp b/Linked List Algo/05. header linked list.cpp
new file mode 100644
index 00000000..8a5d9c21
--- /dev/null
+++ b/Linked List Algo/05. header linked list.cpp	
@@ -0,0 +1,93 @@
+/*
+     hare krishna hare krishna krishna krishna hare hare
+     hare rama hare rama rama rama hare
+*/
+
+//// happy coding ////
+//// chant hare krishna /////
+//// rk dagar ///////
+
+#include<bits/stdc++.h>
+using namespace std;
+
+class node{
+	public:
+		int data;
+		node *next;
+		node(int n)
+		{
+			data=n;
+			next=NULL;
+		}
+			node()
+		{
+			data=0;
+			next=NULL;
+		}
+};
+
+node *start = NULL;
+node *createll(node *);
+node *display(node *);
+int main()
+{
+	int option;
+	do{
+		cout<<"\n\n *******MAIN MENU*******";
+		cout<<"\n 1:  Create a header linked list ";
+		cout<<"\n 2:  Display the header linked list ";
+		cout<<"\n 3:  exit\n";
+		cin>>option;
+		switch(option)
+		{
+			case 1:
+				start= createll(start);
+				cout<<"\nheader linked list created";
+				break;
+			case 2:
+				start= display(start);
+				break;
+
+		}
+	}while(option!=3);
+	
+	return 0;
+}
+
+node* createll(node *start)
+{
+	node* n,*p;
+	int num;
+	cout<<"\nenter -1 to end\n";
+	cin>>num;
+	while(num!=-1)
+	{
+		n=new node(num);
+		if(start==NULL)
+		{		
+		    start = new node();
+		    start->next=n;
+		}
+		else
+		{
+			p=start;
+			while(p->next!=NULL)
+				p=p->next;
+			p->next=n;
+		}
+		cin>>num;
+	}
+	return start;
+}
+node *display(node* start)
+{
+	node *t=start;
+	while(t!=NULL)
+	{
+		cout<<t->data<<" -> ";
+		t=t->next;
+	}
+	cout<<"NULL\n";
+	return start;
+}
+
diff --git a/Linked List Algo/06. Addition and Subtraction on two polynomials.cpp b/Linked List Algo/06. Addition and Subtraction on two polynomials.cpp
new file mode 100644
index 00000000..c6f0639c
--- /dev/null
+++ b/Linked List Algo/06. Addition and Subtraction on two polynomials.cpp	
@@ -0,0 +1,215 @@
+/*
+     hare krishna hare krishna krishna krishna hare hare
+     hare rama hare rama rama rama hare
+*/
+#include<bits/stdc++.h>
+using namespace std;
+int n,c,num,val;
+class node{
+	public:
+		int num,coeff;
+		node *next;
+		node(int n,int c)
+		{
+			num=n;
+			coeff=c;
+			next=NULL;
+		}
+		node()
+		{
+			num=0,coeff=0;
+			next=NULL;
+		}
+};
+
+node *start1 = NULL,*start2=NULL,*start3=NULL,*start4=NULL;
+
+
+node* createll(node *start)
+{
+	node* n,*p;
+	cout<<"\nenter -1 to end\n";
+	cin>>num>>c;
+	while(num!=-1)
+	{
+		n=new node(num,c);
+		if(start==NULL)
+		{	
+		    start=n;
+		}
+		else
+		{
+			p=start;
+			while(p->next!=NULL)
+				p=p->next;
+			p->next=n;
+		}
+		cin>>num;
+		if(num==-1)
+		break;
+		cin>>c;
+	}
+	return start;
+}
+node *display(node* start)
+{
+	node *t=start;
+	while(t!=NULL)
+	{
+		cout<<t->num<<" x ^ "<<t->coeff<<" -> ";
+		t=t->next;
+	}
+	cout<<"NULL\n";
+	return start;
+}
+node *addnode(node *start,int num,int c)
+{
+	node *p,*n;
+	n=new node(num,c);
+	if(start==NULL)
+	{
+		start=n;
+	}
+	else
+	{
+		p=start;
+		while(p->next!=NULL)
+		p=p->next;
+		p->next=n;
+	}
+	return start;
+}
+node *addpoly(node *start3,node* a,node *b)
+{
+	node *p1=a,*p2=b;
+	int sum;
+	while(p1!=NULL&&p2!=NULL)
+	{
+		if(p1->coeff==p2->coeff)
+		{
+			sum= p1->num+p2->num;
+			start3 = addnode(start3,sum,p1->coeff);
+			p1=p1->next;
+			p2=p2->next;
+		}
+		else if(p1->coeff>p2->coeff)
+		{
+			start3= addnode(start3,p1->num,p1->coeff);
+			p1=p1->next;
+		}
+		else if(p2->coeff>p1->coeff)
+		{
+			start3= addnode(start3,p2->num,p2->coeff);
+			p2=p2->next;
+		}		
+	}
+	if(p1==NULL)
+	{
+		while(p2!=NULL)
+		{
+			start3= addnode(start3,p2->num,p2->coeff);
+			p2=p2->next;
+		}
+	}
+	if(p2==NULL)
+	{
+		while(p1!=NULL)
+		{
+			start3= addnode(start3,p1->num,p1->coeff);
+			p1=p1->next;
+		}
+	}
+	return start3;
+}
+node *subpoly(node *s4,node *a,node *b)
+{
+    int diff;
+	node *p1=a, *p2=b;
+	while(p1!=NULL&&p2!=NULL)
+	{
+		if(p1->coeff==p2->coeff)
+		{
+			diff= p1->num - p2->num;
+			s4= addnode(s4,diff,p1->coeff);
+			p1=p1->next;
+			p2=p2->next;
+		}
+		else if(p1->coeff>p2->coeff)
+		{
+			s4= addnode(s4,p1->num,p1->coeff);
+			p1=p1->next;
+		}
+		else if(p2->coeff>p1->coeff)
+		{
+			s4= addnode(s4,p2->num,p2->coeff);
+			p2=p2->next;
+		}
+	}
+	if(p1==NULL)
+	{
+		while(p2!=NULL)
+		{
+				s4= addnode(s4,p2->num,p2->coeff);
+			p2=p2->next;
+			
+		}
+	}
+	if(p2==NULL)
+	{
+		while(p1!=NULL)
+		{
+				s4= addnode(s4,p1->num,p1->coeff);
+			p1=p1->next;
+		}
+	}
+	
+	return s4;
+}
+int main()
+{
+	int option;
+	do{
+		cout<<"\n\n *******MAIN MENU*******";
+		cout<<"\n 1:  Enter First Polynomial ";
+		cout<<"\n 2:  Display First Polynomial ";
+		cout<<"\n 3:  Enter Second Polynomial";
+		cout<<"\n 4:  Display Second Polynomial";
+		cout<<"\n 5:  Add the Polynomials";
+		cout<<"\n 6:  Display the add result Polynomial";
+		cout<<"\n 7:  Subtract the polynomials";
+		cout<<"\n 8:  Display the subtract result polynomial";
+		cout<<"\n 9:  exit\n";
+		cin>>option;
+		switch(option)
+		{
+			case 1:
+				start1= createll(start1);
+				break;
+			case 2:
+				display(start1);
+				break;
+			case 3:
+				start2= createll(start2);
+				break;
+			case 4:
+				display(start2);
+				break;
+			case 5:
+				start3= addpoly(start3,start1,start2);
+				break;
+			case 6:
+				display(start3);
+				break;
+			case 7:
+				start4= subpoly(start4,start1,start2);
+				break;
+			case 8:
+				display(start4);
+				break;
+
+    	}
+	}while(option!=9);
+	
+	return 0;
+}
+