use methods that allows better handling of dummies

Assignment_2/Node.cpp

@@ -3,12 +3,38 @@
 class Node { 
 public: 
     int data; 
+    bool is_dummy;
     Node* next;
     std::mutex mut; 
     public:
+        Node(int element);
+        static Node* Dummy();
         void lock();
         void unlock();
+        bool is_smaller_than(int n);
+        bool is_equal(int n);
 };
+Node::Node(int element){
+    this->data = element;
+    this->is_dummy = false;
+}
+
+Node* Node::Dummy(){
+    Node* n = new Node(0);
+    n->is_dummy = true;
+    return n;
+}
+
+bool Node::is_smaller_than(int n) {
+    // Everything is smaller than a dummy -> false
+    return  this->data < n && !this->is_dummy;
+}
+
+bool Node::is_equal(int n) {
+    // Dummies are not equal to any number -> false
+    return  this->data == n && !this->is_dummy;
+}
+
 void Node::lock() {
     this->mut.lock();
 }