diff --git a/Assignment_2/FineList.cpp b/Assignment_2/FineList.cpp
index 6276b8f..04b044a 100644
--- a/Assignment_2/FineList.cpp
+++ b/Assignment_2/FineList.cpp
@@ -1,10 +1,13 @@
+#pragma once
+
 #include <bits/stdc++.h>
 
 #include"Node.cpp"
+#include"Set.cpp"
 
 // TODO: implement fine grained locking
 
-class FineSet {
+class FineSet:public Set {
     Node* first;
     public:
         FineSet();
@@ -13,11 +16,7 @@ class FineSet {
         bool ctn(int element);
 };
 
-FineSet::FineSet(){
-    first = Node::Dummy(); // dummy node;
-    Node* last = Node::Dummy();
-    first->next = last;
-}
+FineSet::FineSet() : Set() { }
 
 bool FineSet::add(int element) {
     this->first->lock();
diff --git a/Assignment_2/LazyList.cpp b/Assignment_2/LazyList.cpp
index 32dc305..419a7cf 100644
--- a/Assignment_2/LazyList.cpp
+++ b/Assignment_2/LazyList.cpp
@@ -1,8 +1,11 @@
+#pragma once
+
 #include <bits/stdc++.h>
 
 #include"Node.cpp"
+#include"Set.cpp"
 
-class LazySet {
+class LazySet:public Set {
     protected:
         Node* first;
         std::tuple<Node*, Node*> locate(int element);
@@ -14,11 +17,7 @@ class LazySet {
         bool ctn(int element);
 };
 
-LazySet::LazySet(){
-    first = Node::Dummy(); // dummy node;
-    Node* last = Node::Dummy();
-    first->next = last;
-}
+LazySet::LazySet() : Set() { }
 
 bool LazySet::add(int element) {
     auto tuple = locate(element);
diff --git a/Assignment_2/OptimisticList.cpp b/Assignment_2/OptimisticList.cpp
index e73cea8..6d1c198 100644
--- a/Assignment_2/OptimisticList.cpp
+++ b/Assignment_2/OptimisticList.cpp
@@ -1,8 +1,11 @@
+#pragma once
+
 #include <bits/stdc++.h>
 
 #include"Node.cpp"
+#include"Set.cpp"
 
-class OptimisticSet {
+class OptimisticSet:public Set {
     protected:
         Node* first;
         bool validate(Node* p, Node* c);
@@ -14,11 +17,7 @@ class OptimisticSet {
         
 };
 
-OptimisticSet::OptimisticSet(){
-    first = Node::Dummy(); // dummy node;
-    Node* last = Node::Dummy();
-    first->next = last;
-}
+OptimisticSet::OptimisticSet() : Set() { }
 
 bool OptimisticSet::add(int element) {
     Node* p;
diff --git a/Assignment_2/Set.cpp b/Assignment_2/Set.cpp
new file mode 100644
index 0000000..9e2622c
--- /dev/null
+++ b/Assignment_2/Set.cpp
@@ -0,0 +1,19 @@
+#pragma once
+
+#include "Node.cpp"
+
+class Set {
+    protected:
+        Set();
+        Node* first;
+    public:
+        virtual bool add(int element);
+        virtual bool rmv(int element);
+        virtual bool ctn(int element);
+};
+
+Set::Set(){
+    first = Node::Dummy(); // dummy node;
+    Node* last = Node::Dummy();
+    first->next = last;
+}
\ No newline at end of file