diff --git a/DFS.cpp b/DFS.cpp
index 187bdc5..46a8de2 100644
--- a/DFS.cpp
+++ b/DFS.cpp
@@ -1,80 +1,80 @@
-#include<bits/stdc++.h> 
-using namespace std; 
-  
-// Graph class represents a directed graph 
-// using adjacency list representation 
-class Graph { 
-    int V;    // No. of vertices 
-  
-    // Pointer to an array containing 
-    // adjacency lists 
-    list<int> *adj; 
-  
-    // A recursive function used by DFS 
-    void DFSUtil(int v, bool visited[]); 
-  
-public: 
-    Graph(int V);   // Constructor 
-  
-    // function to add an edge to graph 
-    void addEdge(int v, int w); 
-  
-    // DFS traversal of the vertices 
-    // reachable from v 
-    void DFS(int v); 
-  
-}; 
-  
-Graph::Graph(int V) { 
-    this->V = V; 
-    adj = new list<int>[V]; 
-} 
-  
-void Graph::addEdge(int v, int w) { 
-    adj[v].push_back(w); // Add w to v’s list. 
-} 
-  
-void Graph::DFSUtil(int v, bool visited[]) { 
-    // Mark the current node as visited and 
-    // print it 
-    visited[v] = true; 
-    cout << v << " "; 
-  
+#include<bits/stdc++.h>
+using namespace std;
+
+// Graph class represents a directed graph
+// using adjacency list representation
+class Graph {
+    int V;    // No. of vertices
+
+    // Pointer to an array containing
+    // adjacency lists
+    list<int> *adj;
+
+    // A recursive function used by DFS
+    void DFSUtil(int v, bool visited[]);
+
+public:
+    Graph(int V);   // Constructor
+
+    // function to add an edge to graph
+    void addEdge(int v, int w);
+
+    // DFS traversal of the vertices
+    // reachable from v
+    void DFS(int v);
+
+};
+
+Graph::Graph(int V) {
+    this->V = V;
+    adj = new list<int>[V];
+}
+
+void Graph::addEdge(int v, int w) {
+    adj[v].push_back(w); // Add w to v’s list.
+}
+
+void Graph::DFSUtil(int v, bool visited[]) {
+    // Mark the current node as visited and
+    // print it
+    visited[v] = true;
+    cout << v << " ";
+
     // Recur for all the vertices adjacent neighbors
-    // to this vertex 
-    for ( int neighbor : adj[v]){ 
-        if (!visited[neighbor]){ 
+    // to this vertex
+    for ( int neighbor : adj[v]) {
+        if (!visited[neighbor]) {
             DFSUtil(neighbor, visited);
         }
     }
-} 
-  
-// DFS traversal of the vertices reachable from v. 
-// It uses recursive DFSUtil() 
-void Graph::DFS(int v) { 
-    // Mark all the vertices as not visited 
-    bool visited[V]; 
-    
+}
+
+// DFS traversal of the vertices reachable from v.
+// It uses recursive DFSUtil()
+void Graph::DFS(int v) {
+    // Mark all the vertices as not visited
+    bool visited[V];
+
     memset(visited, false, sizeof(visited));
-  
-    // Call the recursive helper function 
-    // to print DFS traversal 
-    DFSUtil(v, visited); 
-} 
-  
-// Driver code 
-int main() { 
-    // Create a graph given in the above diagram 
-    Graph g(4); 
-    g.addEdge(0, 1); 
-    g.addEdge(0, 2); 
-    g.addEdge(1, 2); 
-    g.addEdge(2, 0); 
-    g.addEdge(2, 3); 
-    g.addEdge(3, 3); 
-  
+
+    // Call the recursive helper function
+    // to print DFS traversal
+    DFSUtil(v, visited);
+}
+
+// Driver code
+int main() {
+    // Create a graph given in the above diagram
+    Graph g(4);
+    g.addEdge(0, 1);
+    g.addEdge(0, 2);
+    g.addEdge(1, 2);
+    g.addEdge(2, 0);
+    g.addEdge(2, 3);
+    g.addEdge(3, 3);
+
     cout << "Following is Depth First Traversal"
-            " (starting from vertex 2) \n"; 
-    g.DFS(2); 
-  
-    return 0; 
+         " (starting from vertex 2) \n";
+    g.DFS(2);
+
+    return 0;
diff --git a/DFS.cpp.orig b/DFS.cpp.orig
new file mode 100644
index 0000000..187bdc5
--- /dev/null
+++ b/DFS.cpp.orig
@@ -0,0 +1,80 @@
+#include<bits/stdc++.h> 
+using namespace std; 
+  
+// Graph class represents a directed graph 
+// using adjacency list representation 
+class Graph { 
+    int V;    // No. of vertices 
+  
+    // Pointer to an array containing 
+    // adjacency lists 
+    list<int> *adj; 
+  
+    // A recursive function used by DFS 
+    void DFSUtil(int v, bool visited[]); 
+  
+public: 
+    Graph(int V);   // Constructor 
+  
+    // function to add an edge to graph 
+    void addEdge(int v, int w); 
+  
+    // DFS traversal of the vertices 
+    // reachable from v 
+    void DFS(int v); 
+  
+}; 
+  
+Graph::Graph(int V) { 
+    this->V = V; 
+    adj = new list<int>[V]; 
+} 
+  
+void Graph::addEdge(int v, int w) { 
+    adj[v].push_back(w); // Add w to v’s list. 
+} 
+  
+void Graph::DFSUtil(int v, bool visited[]) { 
+    // Mark the current node as visited and 
+    // print it 
+    visited[v] = true; 
+    cout << v << " "; 
+  
+    // Recur for all the vertices adjacent neighbors
+    // to this vertex 
+    for ( int neighbor : adj[v]){ 
+        if (!visited[neighbor]){ 
+            DFSUtil(neighbor, visited);
+        }
+    }
+} 
+  
+// DFS traversal of the vertices reachable from v. 
+// It uses recursive DFSUtil() 
+void Graph::DFS(int v) { 
+    // Mark all the vertices as not visited 
+    bool visited[V]; 
+    
+    memset(visited, false, sizeof(visited));
+  
+    // Call the recursive helper function 
+    // to print DFS traversal 
+    DFSUtil(v, visited); 
+} 
+  
+// Driver code 
+int main() { 
+    // Create a graph given in the above diagram 
+    Graph g(4); 
+    g.addEdge(0, 1); 
+    g.addEdge(0, 2); 
+    g.addEdge(1, 2); 
+    g.addEdge(2, 0); 
+    g.addEdge(2, 3); 
+    g.addEdge(3, 3); 
+  
+    cout << "Following is Depth First Traversal"
+            " (starting from vertex 2) \n"; 
+    g.DFS(2); 
+  
+    return 0; 
diff --git a/dataabstruction.cpp b/dataabstruction.cpp
index 02a41c3..cafcb9a 100644
--- a/dataabstruction.cpp
+++ b/dataabstruction.cpp
@@ -1,20 +1,21 @@
-#include <iostream>    
-using namespace std;    
- class Sum    
-{    
-private: int x, y, z; // private variables  are providing data abstraction in this program
-public:    
-void add()    
-{    
-cout<<"Enter two numbers: ";    
-cin>>x>>y;    
-z= x+y;    
-cout<<"Sum of two number is: "<<z<<endl;    
-}    
-};    
-int main()    
-{    
-Sum sm;    
-sm.add();    
-return 0;    
-}    
\ No newline at end of file
+#include <iostream>
+using namespace std;
+class Sum
+{
+private:
+    int x, y, z; // private variables  are providing data abstraction in this program
+public:
+    void add()
+    {
+        cout<<"Enter two numbers: ";
+        cin>>x>>y;
+        z= x+y;
+        cout<<"Sum of two number is: "<<z<<endl;
+    }
+};
+int main()
+{
+    Sum sm;
+    sm.add();
+    return 0;
+}
\ No newline at end of file
diff --git a/dataabstruction.cpp.orig b/dataabstruction.cpp.orig
new file mode 100644
index 0000000..02a41c3
--- /dev/null
+++ b/dataabstruction.cpp.orig
@@ -0,0 +1,20 @@
+#include <iostream>    
+using namespace std;    
+ class Sum    
+{    
+private: int x, y, z; // private variables  are providing data abstraction in this program
+public:    
+void add()    
+{    
+cout<<"Enter two numbers: ";    
+cin>>x>>y;    
+z= x+y;    
+cout<<"Sum of two number is: "<<z<<endl;    
+}    
+};    
+int main()    
+{    
+Sum sm;    
+sm.add();    
+return 0;    
+}    
\ No newline at end of file
diff --git a/doubly_linkedlist.cpp b/doubly_linkedlist.cpp
index b5193c3..5e500ba 100644
--- a/doubly_linkedlist.cpp
+++ b/doubly_linkedlist.cpp
@@ -2,31 +2,21 @@
 using namespace std;
 struct node
 {
-	int data;
-	node *prev;
-	node *next;
+    int data;
+    node *prev;
+    node *next;
 };
 
-class doublylist{
+class doublylist {
 private:
-	node *head,*tail;
+    node *head,*tail;
 public:
-	doublylist()
-	{
-		head=NULL;
-		tail=NULL;
-	}
-  void addtohead(int value)
-  {
-    node *newNode=new node;
-    newNode -> data = value;
-    newNode -> prev = NULL;
-    if(head == NULL)
+    doublylist()
     {
-       newNode -> next = NULL;
-       head = newNode;
+        head=NULL;
+        tail=NULL;
     }
-    else
+    void addtohead(int value)
     {
        newNode -> next = head;
        head = newNode;
@@ -129,136 +119,244 @@ void search_element(int data)
     {
         if(temp -> data == data)   // Element is found
         {
-            
-            flag=1;//If found, print and exit
-            break;
-        
+            newNode -> next = NULL;
+            head = newNode;
         }
         else
         {
-            temp = temp ->next;         //If not found, traverse the list
-            pos++;
+            newNode -> next = head;
+            head = newNode;
         }
+        cout<<"\nInsertion successful at the head"<<endl;
     }
-    if(flag==1)
+
+    void insertAtEnd(int v)
     {
-        cout<<"\nThe element  is  found in the list";
+        node *newNode=new node;
+        newNode -> data = v;
+        newNode -> next = NULL;
+        if(head == NULL)
+        {
+            newNode -> prev= NULL;
+            head = newNode;
+        }
+        else
+        {   node *temp = head;
+            while(temp -> next != NULL)
+                temp = temp -> next;
+            temp -> next = newNode;
+            newNode -> prev = temp;
+        }
+        cout<<"\nInsertion success!!! at the end"<<endl;
     }
-    else
+    void deleteBeginning()
     {
-    cout<<"\nThe element  is not found in the list";
-    } 
-}
-void deleteFromN(int position)
-{
-    node *current;
-    current = head;
-    for(int i=1; i<position && current!=NULL; i++)
+        if(head == NULL)
+            cout<<"List is Empty!!! Deletion not possible!!!"<<endl;
+        else
+        {
+            node *temp = head;
+            if(temp->prev== temp->next)
+            {
+                head = NULL;
+                delete temp;
+            }
+            else {
+                head = temp->next;
+                head->prev = NULL;
+                delete temp;
+            }
+            cout<<"Deletion success at the front"<<endl;
+        }
+    }
+    void deleteEnd()
     {
-        current = current->next;
+        if(head == NULL)
+            cout<<"List is Empty!!! Deletion not possible"<<endl;
+        else
+        {
+            node *temp = head;
+            if(temp->prev == temp->next)
+            {
+                head = NULL;
+                delete temp;
+            }
+            else {
+                while(temp->next != NULL)
+                    temp = temp->next;
+                temp->prev ->next = NULL;
+                delete temp;
+            }
+            cout<<"Deletion successful at the end "<<endl;
+        }
     }
-    if(position == 0)
+    void insert_specified(int item)
+    {   node *ptr = new node;
+        node *temp;
+        int loc;
+        if(ptr == NULL)
+        {
+            cout<<"\nOVERFLOW";
+        }
+        else
+        {
+            cout<<"Enter the location\n";
+            cin>>loc;
+            temp=head;
+            for(int i=0; i<loc; i++)
+            {
+                temp = temp->next;
+            }
+            ptr->data = item;
+            ptr->next = temp->next;
+            ptr -> prev = temp;
+            temp->next = ptr;
+            temp->next->prev=ptr;
+            cout<<"Node Inserted at the desired position \n";
+        }
+    }
+    void search_element(int data)
     {
-       deleteBeginning();
+        node * temp = new node;
+        temp = head;
+        int pos = 0;
+        int flag=0;
+        while(temp != NULL)
+        {
+            if(temp -> data == data)   // Element is found
+            {
+
+                flag=1;//If found, print and exit
+                break;
+
+            }
+            else
+            {
+                temp = temp ->next;         //If not found, traverse the list
+                pos++;
+            }
+        }
+        if(flag==1)
+        {
+            cout<<"\nThe element  is  found in the list";
+        }
+        else
+        {
+            cout<<"\nThe element  is not found in the list";
+        }
     }
-    else if(current != NULL)
+    void deleteFromN(int position)
     {
-        current->prev->next = current->next;
-        current->next->prev = current->prev;
-        delete current; 
-        cout<<"SUCCESSFULLY DELETED NODE FROM POSITION.\n";
+        node *current;
+        current = head;
+        for(int i=1; i<position && current!=NULL; i++)
+        {
+            current = current->next;
+        }
+        if(position == 0)
+        {
+            deleteBeginning();
+        }
+        else if(current != NULL)
+        {
+            current->prev->next = current->next;
+            current->next->prev = current->prev;
+            delete current;
+            cout<<"SUCCESSFULLY DELETED NODE FROM POSITION.\n";
+        }
+        else
+        {
+            cout<<"Invalid position!\n";
+        }
     }
-    else
+    void reverse()
     {
-        cout<<"Invalid position!\n";
+        node *current = head;
+        node *temp = NULL;
+        while(current!=NULL)
+        {
+            temp = current->prev;   //swap the next and prev pointer
+            current->prev = current->next;
+            current->next = temp;
+            current = current->prev;
+        }
+        temp->prev;
+        cout<<"LIST REVERSED SUCCESSFULLY.\n";
     }
-}
-void reverse()
-{
-    node *current = head;
-    node *temp = NULL;
-    while(current!=NULL)
+    void display()
     {
-      temp = current->prev;   //swap the next and prev pointer
-      current->prev = current->next;
-      current->next = temp;
-      current = current->prev;
+        node *ptr;
+        cout<<"printing values"<<endl;
+        ptr = head;
+        while(ptr != NULL)
+        {
+            cout<<ptr->data<<"->"<<" ";
+            ptr=ptr->next;
+        }
     }
-    temp->prev;
-    cout<<"LIST REVERSED SUCCESSFULLY.\n";
-}
- void display()  
-{  
-    node *ptr;  
-    cout<<"printing values"<<endl;  
-    ptr = head;  
-    while(ptr != NULL)  
-    {  
-        cout<<ptr->data<<"->"<<" ";  
-        ptr=ptr->next;  
-    }  
-}  
 };
 int main()
-{doublylist d;
- while(1)
- {      int n;
- 	cout<<endl;
- 	cout<<"enter you choice"<<endl;
- 	cout<<"1. add to head"<<endl;
- 	cout<<"2. add to end"<<endl;
- 	cout<<"3. delete from head"<<endl;
+{   doublylist d;
+    while(1)
+    {   int n;
+        cout<<endl;
+        cout<<"enter you choice"<<endl;
+        cout<<"1. add to head"<<endl;
+        cout<<"2. add to end"<<endl;
+        cout<<"3. delete from head"<<endl;
         cout<<"4. delete from end"<<endl;
- 	cout<<"5. display"<<endl;
- 	cout<<"6. insert  at desired position"<<endl;
+        cout<<"5. display"<<endl;
+        cout<<"6. insert  at desired position"<<endl;
         cout<<"7. search  in doubly linked list"<<endl;
         cout<<"8. delete from desired position"<<endl;
         cout<<"9. reverse"<<endl;
-    cin>>n;
-    switch(n)
-    {
-    	case 1:
-    	int m;
-    	cout<<"enter item to add to head"<<endl;
-    	cin>>m;
-    	d.addtohead(m);
-    	break;
-    	case 2:
-    	int item;
-    	cout<<"enter item to add to head"<<endl;
-    	cin>>item;
-    	d.insertAtEnd(item);
-    	break; 
+        cin>>n;
+        switch(n)
+        {
+        case 1:
+            int m;
+            cout<<"enter item to add to head"<<endl;
+            cin>>m;
+            d.addtohead(m);
+            break;
+        case 2:
+            int item;
+            cout<<"enter item to add to head"<<endl;
+            cin>>item;
+            d.insertAtEnd(item);
+            break;
         case 3:
-       d.deleteBeginning();
-       break;
-       case 4:
-       d.deleteEnd();
-       break;
-       case 5:
-       d.display();
-       break;
-       case 6:
-      int newvalue;
-      cout<<"enter value for desired position\n";
-      cin>>newvalue;
-      d.insert_specified(newvalue);
-      break;
-      case 7:
-      int newvalue1;
-      cout<<"enter value for searching position\n";
-      cin>>newvalue1;
-      d.search_element(newvalue1);
-      break;
-      case 8:
-      int newvalue2;
-      cout<<"enter position desired for deletion \n";
-      cin>>newvalue2;
-      d.deleteFromN(newvalue2);
-      break;
-      case 9:
-      d.reverse();
-      break;
-      default:
-      cout<<"exit successfull";}}
+            d.deleteBeginning();
+            break;
+        case 4:
+            d.deleteEnd();
+            break;
+        case 5:
+            d.display();
+            break;
+        case 6:
+            int newvalue;
+            cout<<"enter value for desired position\n";
+            cin>>newvalue;
+            d.insert_specified(newvalue);
+            break;
+        case 7:
+            int newvalue1;
+            cout<<"enter value for searching position\n";
+            cin>>newvalue1;
+            d.search_element(newvalue1);
+            break;
+        case 8:
+            int newvalue2;
+            cout<<"enter position desired for deletion \n";
+            cin>>newvalue2;
+            d.deleteFromN(newvalue2);
+            break;
+        case 9:
+            d.reverse();
+            break;
+        default:
+            cout<<"exit successfull";
+        }
+    }
 }
diff --git a/doubly_linkedlist.cpp.orig b/doubly_linkedlist.cpp.orig
new file mode 100644
index 0000000..b5193c3
--- /dev/null
+++ b/doubly_linkedlist.cpp.orig
@@ -0,0 +1,264 @@
+#include<iostream>
+using namespace std;
+struct node
+{
+	int data;
+	node *prev;
+	node *next;
+};
+
+class doublylist{
+private:
+	node *head,*tail;
+public:
+	doublylist()
+	{
+		head=NULL;
+		tail=NULL;
+	}
+  void addtohead(int value)
+  {
+    node *newNode=new node;
+    newNode -> data = value;
+    newNode -> prev = NULL;
+    if(head == NULL)
+    {
+       newNode -> next = NULL;
+       head = newNode;
+    }
+    else
+    {
+       newNode -> next = head;
+       head = newNode;
+    }
+    cout<<"\nInsertion successful at the head"<<endl;
+ }
+
+void insertAtEnd(int v)
+{  
+	node *newNode=new node;
+   newNode -> data = v;
+   newNode -> next = NULL;
+   if(head == NULL)
+   {
+      newNode -> prev= NULL;
+      head = newNode;
+   }
+   else
+   {  node *temp = head;
+      while(temp -> next != NULL)
+      temp = temp -> next;
+      temp -> next = newNode;
+      newNode -> prev = temp;
+   }
+   cout<<"\nInsertion success!!! at the end"<<endl;   
+}
+void deleteBeginning()
+{
+   if(head == NULL)
+      cout<<"List is Empty!!! Deletion not possible!!!"<<endl;
+   else
+   {
+      node *temp = head;
+      if(temp->prev== temp->next)
+      {
+         head = NULL;
+         delete temp;
+      }
+      else{
+         head = temp->next;
+         head->prev = NULL;
+         delete temp;
+      }
+      cout<<"Deletion success at the front"<<endl;
+   }
+}
+void deleteEnd()
+{
+   if(head == NULL)
+      cout<<"List is Empty!!! Deletion not possible"<<endl;
+   else
+   {
+      node *temp = head;
+      if(temp->prev == temp->next)
+      {
+         head = NULL;
+         delete temp;
+      }
+      else{
+         while(temp->next != NULL)
+            temp = temp->next;
+         temp->prev ->next = NULL;
+         delete temp;
+      }
+      cout<<"Deletion successful at the end "<<endl;
+   }
+}
+void insert_specified(int item)  
+{  node *ptr = new node;  
+   node *temp;   
+   int loc;   
+   if(ptr == NULL)  
+   {  
+       cout<<"\nOVERFLOW";  
+   }  
+   else  
+   {  
+       cout<<"Enter the location\n";  
+       cin>>loc;   
+       temp=head;  
+       for(int i=0;i<loc;i++)  
+       {  
+           temp = temp->next;   
+       }  
+       ptr->data = item;  
+       ptr->next = temp->next;  
+       ptr -> prev = temp;  
+       temp->next = ptr;  
+       temp->next->prev=ptr;  
+       cout<<"Node Inserted at the desired position \n";  
+   }  
+}
+void search_element(int data)
+{
+     node * temp = new node;
+    temp = head;
+    int pos = 0;
+    int flag=0;
+    while(temp != NULL)
+    {
+        if(temp -> data == data)   // Element is found
+        {
+            
+            flag=1;//If found, print and exit
+            break;
+        
+        }
+        else
+        {
+            temp = temp ->next;         //If not found, traverse the list
+            pos++;
+        }
+    }
+    if(flag==1)
+    {
+        cout<<"\nThe element  is  found in the list";
+    }
+    else
+    {
+    cout<<"\nThe element  is not found in the list";
+    } 
+}
+void deleteFromN(int position)
+{
+    node *current;
+    current = head;
+    for(int i=1; i<position && current!=NULL; i++)
+    {
+        current = current->next;
+    }
+    if(position == 0)
+    {
+       deleteBeginning();
+    }
+    else if(current != NULL)
+    {
+        current->prev->next = current->next;
+        current->next->prev = current->prev;
+        delete current; 
+        cout<<"SUCCESSFULLY DELETED NODE FROM POSITION.\n";
+    }
+    else
+    {
+        cout<<"Invalid position!\n";
+    }
+}
+void reverse()
+{
+    node *current = head;
+    node *temp = NULL;
+    while(current!=NULL)
+    {
+      temp = current->prev;   //swap the next and prev pointer
+      current->prev = current->next;
+      current->next = temp;
+      current = current->prev;
+    }
+    temp->prev;
+    cout<<"LIST REVERSED SUCCESSFULLY.\n";
+}
+ void display()  
+{  
+    node *ptr;  
+    cout<<"printing values"<<endl;  
+    ptr = head;  
+    while(ptr != NULL)  
+    {  
+        cout<<ptr->data<<"->"<<" ";  
+        ptr=ptr->next;  
+    }  
+}  
+};
+int main()
+{doublylist d;
+ while(1)
+ {      int n;
+ 	cout<<endl;
+ 	cout<<"enter you choice"<<endl;
+ 	cout<<"1. add to head"<<endl;
+ 	cout<<"2. add to end"<<endl;
+ 	cout<<"3. delete from head"<<endl;
+        cout<<"4. delete from end"<<endl;
+ 	cout<<"5. display"<<endl;
+ 	cout<<"6. insert  at desired position"<<endl;
+        cout<<"7. search  in doubly linked list"<<endl;
+        cout<<"8. delete from desired position"<<endl;
+        cout<<"9. reverse"<<endl;
+    cin>>n;
+    switch(n)
+    {
+    	case 1:
+    	int m;
+    	cout<<"enter item to add to head"<<endl;
+    	cin>>m;
+    	d.addtohead(m);
+    	break;
+    	case 2:
+    	int item;
+    	cout<<"enter item to add to head"<<endl;
+    	cin>>item;
+    	d.insertAtEnd(item);
+    	break; 
+        case 3:
+       d.deleteBeginning();
+       break;
+       case 4:
+       d.deleteEnd();
+       break;
+       case 5:
+       d.display();
+       break;
+       case 6:
+      int newvalue;
+      cout<<"enter value for desired position\n";
+      cin>>newvalue;
+      d.insert_specified(newvalue);
+      break;
+      case 7:
+      int newvalue1;
+      cout<<"enter value for searching position\n";
+      cin>>newvalue1;
+      d.search_element(newvalue1);
+      break;
+      case 8:
+      int newvalue2;
+      cout<<"enter position desired for deletion \n";
+      cin>>newvalue2;
+      d.deleteFromN(newvalue2);
+      break;
+      case 9:
+      d.reverse();
+      break;
+      default:
+      cout<<"exit successfull";}}
+}
diff --git a/encapsulation.cpp b/encapsulation.cpp
index c9956f9..0f01b0b 100644
--- a/encapsulation.cpp
+++ b/encapsulation.cpp
@@ -1,7 +1,7 @@
 
 #include<iostream>
 using namespace std;
-class ExampleEncap{
+class ExampleEncap {
 private:
    int num;
    char ch;
@@ -27,4 +27,5 @@ int main(){
    cout<<obj.getNum()<<endl;
    cout<<obj.getCh()<<endl;
    return 0;
+
 }
diff --git a/encapsulation.cpp.orig b/encapsulation.cpp.orig
new file mode 100644
index 0000000..c9956f9
--- /dev/null
+++ b/encapsulation.cpp.orig
@@ -0,0 +1,30 @@
+
+#include<iostream>
+using namespace std;
+class ExampleEncap{
+private:
+   int num;
+   char ch;
+public:
+   int getNum() const {
+      return num;
+   }
+   char getCh() const {
+      return ch;
+   }
+
+   void setNum(int num) {
+      this->num = num;
+   }
+   void setCh(char ch) {
+      this->ch = ch;
+   }
+};
+int main(){
+   ExampleEncap obj;
+   obj.setNum(100);
+   obj.setCh('A');
+   cout<<obj.getNum()<<endl;
+   cout<<obj.getCh()<<endl;
+   return 0;
+}
diff --git a/singly_linkedlist.cpp b/singly_linkedlist.cpp
index f73fd06..07356c0 100644
--- a/singly_linkedlist.cpp
+++ b/singly_linkedlist.cpp
@@ -2,18 +2,18 @@
 using namespace std;
 struct  node
 {
-	int data;
-	node *next;
+    int data;
+    node *next;
 };
 class singlelist
 {
- private:
- 	node *tail,*head;
- public:
- 	singlelist()
- 	{   head=NULL;
- 		tail=NULL;
- 	}
+private:
+    node *tail,*head;
+public:
+    singlelist()
+    {   head=NULL;
+        tail=NULL;
+    }
     void addtotail(int n)
     {
         node *tmp = new node;
@@ -23,134 +23,134 @@ class singlelist
         {
             head = tmp;
             tail = tmp;
-	}else
-	{
+        } else
+        {
             tail->next = tmp;
             tail = tail->next;
         }
         cout<<"succesfully added to tail";
     }
-  void addtohead(int val)
-  {    node *new_node = new node;
-      new_node->data = val;
-      new_node->next = NULL;
-      if (head == NULL)
-      {
-        head = new_node;
-      } else
-      {
-        new_node->next = head;
-        head= new_node;
-      }
-      cout<<"succesfully added to head";
+    void addtohead(int val)
+    {   node *new_node = new node;
+        new_node->data = val;
+        new_node->next = NULL;
+        if (head == NULL)
+        {
+            head = new_node;
+        } else
+        {
+            new_node->next = head;
+            head= new_node;
+        }
+        cout<<"succesfully added to head";
     }
- void randominsert(int itemn)  
-    {  
+    void randominsert(int itemn)
+    {
         node *ptr = new node;
-        struct node *temp;  
-        int loc;  
-            cout<<"Enter the location";  
-            cin>>loc; 
-           
-            ptr->data = itemn;  
-            temp=head;  
-            for(int i=0;i<loc;i++)  
-            {   temp = temp->next;  
-                if(temp == NULL)  
-                {  
-                    cout<<"\ncan't insert\n";  
-                    return;  
-                }  
-            }  
-            ptr ->next = temp ->next;   
-            temp ->next = ptr; 
-            cout<<"\nNode inserted at desired position"; 
-              }  
-  void begdelete()  
-    {  
-        node *ptr;  
-        if(head == NULL)  
-        {  
-            cout<<"\nList is empty";  
-        }  
-        else   
-        {  
-            ptr = head;  
-            head = ptr->next;  
-            delete ptr;  
-            cout<<"\n Node deleted from the begining ...";  
-        }  
-           } 
-void end_delete()  
-    {  
-        struct node *ptr,*ptr1;  
-        if(head == NULL)  
-        {  
-            cout<<"\nlist is empty";  
-        }  
-        else if(head -> next == NULL)  
-        {  
-            head = NULL;  
-            delete head;  
-            cout<<"\nOnly node of the list deleted ...";  
-        }       
-        else  
-        {   ptr = head;   
-            while(ptr->next != NULL)  
-                {  
-                    ptr1 = ptr;  
-                    ptr = ptr ->next;  
-                }  
-                ptr1->next = NULL;  
-                delete ptr;  
-                cout<<"\n Deleted Node from the last ...";  
-            }     
-        }  
-void search(int key)
-{   
-	struct node *search;
-	search=head;
-    while (search->next!= NULL)
+        struct node *temp;
+        int loc;
+        cout<<"Enter the location";
+        cin>>loc;
+
+        ptr->data = itemn;
+        temp=head;
+        for(int i=0; i<loc; i++)
+        {   temp = temp->next;
+            if(temp == NULL)
+            {
+                cout<<"\ncan't insert\n";
+                return;
+            }
+        }
+        ptr ->next = temp ->next;
+        temp ->next = ptr;
+        cout<<"\nNode inserted at desired position";
+    }
+    void begdelete()
     {
-        if (search->data == key)
+        node *ptr;
+        if(head == NULL)
         {
-            cout<<"element is found in list\n";
-            return;
+            cout<<"\nList is empty";
+        }
+        else
+        {
+            ptr = head;
+            head = ptr->next;
+            delete ptr;
+            cout<<"\n Node deleted from the begining ...";
         }
-        search = search->next;
-    }
-    cout<<"item not found in list\n";
-}
-void Delete(int anypos)
-{    node* temp1 = head;
-    if(anypos == 1){
-        head = temp1->next;
-        delete temp1;
-        cout<<"succesfully deleted from desired positon in list\n"<<endl;
     }
-    else
+    void end_delete()
     {
-    for(int i=0;i<anypos-2;i++)
+        struct node *ptr,*ptr1;
+        if(head == NULL)
+        {
+            cout<<"\nlist is empty";
+        }
+        else if(head -> next == NULL)
+        {
+            head = NULL;
+            delete head;
+            cout<<"\nOnly node of the list deleted ...";
+        }
+        else
+        {   ptr = head;
+            while(ptr->next != NULL)
+            {
+                ptr1 = ptr;
+                ptr = ptr ->next;
+            }
+            ptr1->next = NULL;
+            delete ptr;
+            cout<<"\n Deleted Node from the last ...";
+        }
+    }
+    void search(int key)
     {
-        temp1 = temp1->next;
+        struct node *search;
+        search=head;
+        while (search->next!= NULL)
+        {
+            if (search->data == key)
+            {
+                cout<<"element is found in list\n";
+                return;
+            }
+            search = search->next;
+        }
+        cout<<"item not found in list\n";
     }
-    node* temp2 = temp1->next; 
-    temp1->next = temp2->next; 
-    delete temp2;
-    cout<<"succesfully deleted from desired positon in list\n"<<endl;
-}
-}
-void reverse() {
-      node *curNode = head ,*nxtNode;
-      head = NULL;
-    while (curNode != NULL) {
-        nxtNode = curNode->next;
-        curNode->next = head;
-        head = curNode;
-        curNode = nxtNode;
+    void Delete(int anypos)
+    {   node* temp1 = head;
+        if(anypos == 1) {
+            head = temp1->next;
+            delete temp1;
+            cout<<"succesfully deleted from desired positon in list\n"<<endl;
+        }
+        else
+        {
+            for(int i=0; i<anypos-2; i++)
+            {
+                temp1 = temp1->next;
+            }
+            node* temp2 = temp1->next;
+            temp1->next = temp2->next;
+            delete temp2;
+            cout<<"succesfully deleted from desired positon in list\n"<<endl;
+        }
     }
-}
-void display()
+    void reverse() {
+        node *curNode = head,*nxtNode;
+        head = NULL;
+        while (curNode != NULL) {
+            nxtNode = curNode->next;
+            curNode->next = head;
+            head = curNode;
+            curNode = nxtNode;
+        }
+    }
+    void display()
     {
         node *tmp;
         tmp = head;
@@ -162,69 +162,69 @@ void display()
     }
 };
 int main()
-{  singlelist l;
-   int n;
-	while(1)
-	{   cout<<endl;
-		cout<<"enter your choice"<<endl;
-		cout<<"1. add to tail"<<endl;
-		cout<<"2. add to head"<<endl;
+{   singlelist l;
+    int n;
+    while(1)
+    {   cout<<endl;
+        cout<<"enter your choice"<<endl;
+        cout<<"1. add to tail"<<endl;
+        cout<<"2. add to head"<<endl;
         cout<<"3. add to desired position"<<endl;
         cout<<"4. delete from front/begin"<<endl;
         cout<<"5. delete from end/last "<<endl;
         cout<<"6. search in list  "<<endl;
         cout<<"7. delete from desired position  "<<endl;
-		cout<<"8. display"<<endl;
-		cout<<"9. reverse"<<endl;
-		cin>>n;
-		switch(n)
-{    
-             case 1:
-			 int item;
-			 cout<<"enter item to tail"<<endl;
-			 cin>>item;
-			 l.addtotail(item);
-			 break;
-             case 2:
-			 int item1;
-			 cout<<"enter item to tail"<<endl;
-			 cin>>item1;
-			 l.addtohead(item1);
-			 break;
-             case 3:
-			 int iteminsert;
-			 cout<<"enter item to desired position"<<endl;
-			 cin>>iteminsert;
-			 l.randominsert(iteminsert);
-			 break;
-             case 4:
-			 l.begdelete();
-			 break;
-             case 5:
-			l.end_delete();
-			 break;
-	     case 6:
-			 int value;
-			 cout<<"enter item you want to search"<<endl;
-			 cin>>value;
-			 l.search(value);
-			 break;
-	     case 7:
-			 int delpos;
-			 cout<<"enter position you want to delete"<<endl;
-			 cin>>delpos;
-			 l.Delete(delpos);
-			 break;
+        cout<<"8. display"<<endl;
+        cout<<"9. reverse"<<endl;
+        cin>>n;
+        switch(n)
+        {
+        case 1:
+            int item;
+            cout<<"enter item to tail"<<endl;
+            cin>>item;
+            l.addtotail(item);
+            break;
+        case 2:
+            int item1;
+            cout<<"enter item to tail"<<endl;
+            cin>>item1;
+            l.addtohead(item1);
+            break;
+        case 3:
+            int iteminsert;
+            cout<<"enter item to desired position"<<endl;
+            cin>>iteminsert;
+            l.randominsert(iteminsert);
+            break;
+        case 4:
+            l.begdelete();
+            break;
+        case 5:
+            l.end_delete();
+            break;
+        case 6:
+            int value;
+            cout<<"enter item you want to search"<<endl;
+            cin>>value;
+            l.search(value);
+            break;
+        case 7:
+            int delpos;
+            cout<<"enter position you want to delete"<<endl;
+            cin>>delpos;
+            l.Delete(delpos);
+            break;
 
-	     case 8:
-			 l.display();
-			 break;
+        case 8:
+            l.display();
+            break;
 
-	     case 9:
-			 l.reverse();
-			 break;
-			 default:
-			 cout<<"nothing"<<endl;
-		}
-	}
+        case 9:
+            l.reverse();
+            break;
+        default:
+            cout<<"nothing"<<endl;
+        }
+    }
 }
diff --git a/singly_linkedlist.cpp.orig b/singly_linkedlist.cpp.orig
new file mode 100644
index 0000000..f73fd06
--- /dev/null
+++ b/singly_linkedlist.cpp.orig
@@ -0,0 +1,230 @@
+#include <iostream>
+using namespace std;
+struct  node
+{
+	int data;
+	node *next;
+};
+class singlelist
+{
+ private:
+ 	node *tail,*head;
+ public:
+ 	singlelist()
+ 	{   head=NULL;
+ 		tail=NULL;
+ 	}
+    void addtotail(int n)
+    {
+        node *tmp = new node;
+        tmp->data = n;
+        tmp->next = NULL;
+        if(head == NULL)
+        {
+            head = tmp;
+            tail = tmp;
+	}else
+	{
+            tail->next = tmp;
+            tail = tail->next;
+        }
+        cout<<"succesfully added to tail";
+    }
+  void addtohead(int val)
+  {    node *new_node = new node;
+      new_node->data = val;
+      new_node->next = NULL;
+      if (head == NULL)
+      {
+        head = new_node;
+      } else
+      {
+        new_node->next = head;
+        head= new_node;
+      }
+      cout<<"succesfully added to head";
+    }
+ void randominsert(int itemn)  
+    {  
+        node *ptr = new node;
+        struct node *temp;  
+        int loc;  
+            cout<<"Enter the location";  
+            cin>>loc; 
+           
+            ptr->data = itemn;  
+            temp=head;  
+            for(int i=0;i<loc;i++)  
+            {   temp = temp->next;  
+                if(temp == NULL)  
+                {  
+                    cout<<"\ncan't insert\n";  
+                    return;  
+                }  
+            }  
+            ptr ->next = temp ->next;   
+            temp ->next = ptr; 
+            cout<<"\nNode inserted at desired position"; 
+              }  
+  void begdelete()  
+    {  
+        node *ptr;  
+        if(head == NULL)  
+        {  
+            cout<<"\nList is empty";  
+        }  
+        else   
+        {  
+            ptr = head;  
+            head = ptr->next;  
+            delete ptr;  
+            cout<<"\n Node deleted from the begining ...";  
+        }  
+           } 
+void end_delete()  
+    {  
+        struct node *ptr,*ptr1;  
+        if(head == NULL)  
+        {  
+            cout<<"\nlist is empty";  
+        }  
+        else if(head -> next == NULL)  
+        {  
+            head = NULL;  
+            delete head;  
+            cout<<"\nOnly node of the list deleted ...";  
+        }       
+        else  
+        {   ptr = head;   
+            while(ptr->next != NULL)  
+                {  
+                    ptr1 = ptr;  
+                    ptr = ptr ->next;  
+                }  
+                ptr1->next = NULL;  
+                delete ptr;  
+                cout<<"\n Deleted Node from the last ...";  
+            }     
+        }  
+void search(int key)
+{   
+	struct node *search;
+	search=head;
+    while (search->next!= NULL)
+    {
+        if (search->data == key)
+        {
+            cout<<"element is found in list\n";
+            return;
+        }
+        search = search->next;
+    }
+    cout<<"item not found in list\n";
+}
+void Delete(int anypos)
+{    node* temp1 = head;
+    if(anypos == 1){
+        head = temp1->next;
+        delete temp1;
+        cout<<"succesfully deleted from desired positon in list\n"<<endl;
+    }
+    else
+    {
+    for(int i=0;i<anypos-2;i++)
+    {
+        temp1 = temp1->next;
+    }
+    node* temp2 = temp1->next; 
+    temp1->next = temp2->next; 
+    delete temp2;
+    cout<<"succesfully deleted from desired positon in list\n"<<endl;
+}
+}
+void reverse() {
+      node *curNode = head ,*nxtNode;
+      head = NULL;
+    while (curNode != NULL) {
+        nxtNode = curNode->next;
+        curNode->next = head;
+        head = curNode;
+        curNode = nxtNode;
+    }
+}
+void display()
+    {
+        node *tmp;
+        tmp = head;
+        while (tmp != NULL)
+        {
+            cout << tmp->data <<"->"<<" ";
+            tmp = tmp->next;
+        }
+    }
+};
+int main()
+{  singlelist l;
+   int n;
+	while(1)
+	{   cout<<endl;
+		cout<<"enter your choice"<<endl;
+		cout<<"1. add to tail"<<endl;
+		cout<<"2. add to head"<<endl;
+        cout<<"3. add to desired position"<<endl;
+        cout<<"4. delete from front/begin"<<endl;
+        cout<<"5. delete from end/last "<<endl;
+        cout<<"6. search in list  "<<endl;
+        cout<<"7. delete from desired position  "<<endl;
+		cout<<"8. display"<<endl;
+		cout<<"9. reverse"<<endl;
+		cin>>n;
+		switch(n)
+{    
+             case 1:
+			 int item;
+			 cout<<"enter item to tail"<<endl;
+			 cin>>item;
+			 l.addtotail(item);
+			 break;
+             case 2:
+			 int item1;
+			 cout<<"enter item to tail"<<endl;
+			 cin>>item1;
+			 l.addtohead(item1);
+			 break;
+             case 3:
+			 int iteminsert;
+			 cout<<"enter item to desired position"<<endl;
+			 cin>>iteminsert;
+			 l.randominsert(iteminsert);
+			 break;
+             case 4:
+			 l.begdelete();
+			 break;
+             case 5:
+			l.end_delete();
+			 break;
+	     case 6:
+			 int value;
+			 cout<<"enter item you want to search"<<endl;
+			 cin>>value;
+			 l.search(value);
+			 break;
+	     case 7:
+			 int delpos;
+			 cout<<"enter position you want to delete"<<endl;
+			 cin>>delpos;
+			 l.Delete(delpos);
+			 break;
+
+	     case 8:
+			 l.display();
+			 break;
+
+	     case 9:
+			 l.reverse();
+			 break;
+			 default:
+			 cout<<"nothing"<<endl;
+		}
+	}
+}
diff --git a/sorting/mergesort.cpp b/sorting/mergesort.cpp
index 53627a4..1c503ef 100644
--- a/sorting/mergesort.cpp
+++ b/sorting/mergesort.cpp
@@ -1,4 +1,4 @@
-#include<iostream>
+#include<bits/stdc++.h>
 using namespace std;
 
 void merge(int *a,int s,int e){
diff --git a/statickeyword.cpp b/statickeyword.cpp
index 19c0c9c..07008c4 100644
--- a/statickeyword.cpp
+++ b/statickeyword.cpp
@@ -1,28 +1,28 @@
 #include<iostream>
 using namespace std;
- class mayank
- {
+class mayank
+{
 
- public:
- 	static int count;
- 	mayank()
- 	{
- 		count++;
- 	}
- 	static int display()
- 	{
- 		cout<<"no of objects"<<count;
- 	}
+public:
+    static int count;
+    mayank()
+    {
+        count++;
+    }
+    static int display()
+    {
+        cout<<"no of objects"<<count;
+    }
 
 
 
 
- };
- int mayank::count=0;
- int main()
- {
- 	mayank obj1;
- 	mayank obj2;
- 	mayank obj3;
- 	cout<<mayank::display();
- }
\ No newline at end of file
+};
+int mayank::count=0;
+int main()
+{
+    mayank obj1;
+    mayank obj2;
+    mayank obj3;
+    cout<<mayank::display();
+}
\ No newline at end of file
diff --git a/statickeyword.cpp.orig b/statickeyword.cpp.orig
new file mode 100644
index 0000000..19c0c9c
--- /dev/null
+++ b/statickeyword.cpp.orig
@@ -0,0 +1,28 @@
+#include<iostream>
+using namespace std;
+ class mayank
+ {
+
+ public:
+ 	static int count;
+ 	mayank()
+ 	{
+ 		count++;
+ 	}
+ 	static int display()
+ 	{
+ 		cout<<"no of objects"<<count;
+ 	}
+
+
+
+
+ };
+ int mayank::count=0;
+ int main()
+ {
+ 	mayank obj1;
+ 	mayank obj2;
+ 	mayank obj3;
+ 	cout<<mayank::display();
+ }
\ No newline at end of file
diff --git a/thispointer.cpp b/thispointer.cpp
index 7be79a1..82efa2e 100644
--- a/thispointer.cpp
+++ b/thispointer.cpp
@@ -2,21 +2,21 @@
 using namespace std;
 class Demo {
 private:
-  int num;
-  char ch;
+    int num;
+    char ch;
 public:
-  void setMyValues(int num, char ch){
-    this->num =num;
-    this->ch=ch;
-  }
-  void displayMyValues(){
-    cout<<num<<endl;
-    cout<<ch;
-  }
+    void setMyValues(int num, char ch) {
+        this->num =num;
+        this->ch=ch;
+    }
+    void displayMyValues() {
+        cout<<num<<endl;
+        cout<<ch;
+    }
 };
-int main(){
-  Demo obj;
-  obj.setMyValues(100, 'A');
-  obj.displayMyValues();
-  return 0;
+int main() {
+    Demo obj;
+    obj.setMyValues(100, 'A');
+    obj.displayMyValues();
+    return 0;
 }
\ No newline at end of file
diff --git a/thispointer.cpp.orig b/thispointer.cpp.orig
new file mode 100644
index 0000000..7be79a1
--- /dev/null
+++ b/thispointer.cpp.orig
@@ -0,0 +1,22 @@
+#include <iostream>
+using namespace std;
+class Demo {
+private:
+  int num;
+  char ch;
+public:
+  void setMyValues(int num, char ch){
+    this->num =num;
+    this->ch=ch;
+  }
+  void displayMyValues(){
+    cout<<num<<endl;
+    cout<<ch;
+  }
+};
+int main(){
+  Demo obj;
+  obj.setMyValues(100, 'A');
+  obj.displayMyValues();
+  return 0;
+}
\ No newline at end of file