diff --git a/librerie/exercise3/binarytree/binarytree.hpp b/librerie/exercise3/binarytree/binarytree.hpp
index df22063..d1be6ad 100755
--- a/librerie/exercise3/binarytree/binarytree.hpp
+++ b/librerie/exercise3/binarytree/binarytree.hpp
@@ -30,14 +30,12 @@ public:
 
   protected:
     Data data;
-
     // Comparison operators
     bool operator==(const Node&) const noexcept; // Comparison of abstract types is possible, but should not be visible.
     bool operator!=(const Node&) const noexcept; // Comparison of abstract types is possible, but should not be visible.
 
     bool EqualNodes(const Node&, const Node&) const;
 
-
   public:
 
     friend class BinaryTree<Data>;
diff --git a/librerie/exercise3/binarytree/lnk/binarytreelnk.cpp b/librerie/exercise3/binarytree/lnk/binarytreelnk.cpp
index c427a70..ce823cc 100755
--- a/librerie/exercise3/binarytree/lnk/binarytreelnk.cpp
+++ b/librerie/exercise3/binarytree/lnk/binarytreelnk.cpp
@@ -151,7 +151,7 @@ bool BinaryTreeLnk<Data>::operator!=(const BinaryTreeLnk<Data>& tree) const noex
 }
 
 template <typename Data>
-struct BinaryTree<Data>::Node& BinaryTreeLnk<Data>::Root() const{
+struct BinaryTreeLnk<Data>::NodeLnk& BinaryTreeLnk<Data>::Root() const{
   if(size==0) throw std::length_error("Empty tree!");
   return *root;
 }
diff --git a/librerie/exercise3/binarytree/lnk/binarytreelnk.hpp b/librerie/exercise3/binarytree/lnk/binarytreelnk.hpp
index 76ed992..b299fb8 100755
--- a/librerie/exercise3/binarytree/lnk/binarytreelnk.hpp
+++ b/librerie/exercise3/binarytree/lnk/binarytreelnk.hpp
@@ -10,13 +10,13 @@ class BinaryTreeLnk : virtual public BinaryTree<Data>{ // Must extend BinaryTree
 
 protected:
 
-  struct NodeLnk : virtual protected BinaryTree<Data>::Node { // Must extend Node
+  struct NodeLnk : virtual public BinaryTree<Data>::Node { // Must extend Node
 
   protected:
 
     using BinaryTree<Data>::Node::data;
-    struct NodeLnk* left;
-    struct NodeLnk* right;
+    struct NodeLnk* left = nullptr;
+    struct NodeLnk* right = nullptr;
 
   public:
     struct NodeLnk& operator=(const NodeLnk&); // Copy assignment of abstract types should not be possible.
@@ -56,14 +56,14 @@ public:
 
   // Specific member functions (inherited from BinaryTree)
 
-  struct BinaryTree<Data>::Node& Root() const override; // Override BinaryTree member (throw std::length_error when empty)
+  NodeLnk& Root() const override; // Override BinaryTree member (throw std::length_error when empty)
 
   // Specific member functions (inherited from Container)
 
   void Clear() override; // Override Container member
 
   // Specific functions
-  
+
   struct BinaryTreeLnk<Data>::NodeLnk* CreateTreeFromLinearContainerInBreadth(const LinearContainer<Data>&,ulong);
   struct BinaryTreeLnk<Data>::NodeLnk* CopyTree(struct BinaryTreeLnk<Data>::Node*);
   void DeleteTree(BinaryTreeLnk<Data>::NodeLnk* node);
diff --git a/librerie/exercise3/binarytree/vec/binarytreevec.cpp b/librerie/exercise3/binarytree/vec/binarytreevec.cpp
index 3d456a2..89e0c35 100755
--- a/librerie/exercise3/binarytree/vec/binarytreevec.cpp
+++ b/librerie/exercise3/binarytree/vec/binarytreevec.cpp
@@ -141,7 +141,7 @@ bool BinaryTreeVec<Data>::operator!=(const BinaryTreeVec& bt) const noexcept{
 }
 
 template <typename Data>
-struct BinaryTree<Data>::Node& BinaryTreeVec<Data>::Root() const{
+struct BinaryTreeVec<Data>::NodeVec& BinaryTreeVec<Data>::Root() const{
   if(size==0) throw std::length_error("Empty tree!");
   return *(tree.Front());
 }
diff --git a/librerie/exercise3/binarytree/vec/binarytreevec.hpp b/librerie/exercise3/binarytree/vec/binarytreevec.hpp
index 858e20c..9a334b2 100755
--- a/librerie/exercise3/binarytree/vec/binarytreevec.hpp
+++ b/librerie/exercise3/binarytree/vec/binarytreevec.hpp
@@ -12,7 +12,7 @@ class BinaryTreeVec : virtual public BinaryTree<Data>{ // Must extend BinaryTree
 
 protected:
 
-  struct NodeVec : virtual protected BinaryTree<Data>::Node { // Must extend Node
+  struct NodeVec : virtual public BinaryTree<Data>::Node { // Must extend Node
 
   protected:
     using BinaryTree<Data>::Node::data;
@@ -33,7 +33,7 @@ protected:
   };
 
 protected:
-  
+
   using BinaryTree<Data>::size;
   Vector<struct BinaryTreeVec<Data>::NodeVec*> tree;
 
@@ -54,7 +54,7 @@ public:
 
   // Specific member functions (inherited from BinaryTree)
 
-  struct BinaryTree<Data>::Node& Root() const override; // Override BinaryTree member (throw std::length_error when empty)
+  NodeVec& Root() const override; // Override BinaryTree member (throw std::length_error when empty)
 
   // Specific member functions (inherited from Container)
 
diff --git a/librerie/exercise3/zmytest/test.hpp b/librerie/exercise3/zmytest/test.hpp
index bbe113e..b2b22b1 100755
--- a/librerie/exercise3/zmytest/test.hpp
+++ b/librerie/exercise3/zmytest/test.hpp
@@ -36,8 +36,8 @@ void menu(){
 
   BinaryTreeLnk<string> bt1(vec);
   BinaryTreeLnk<string> bt2(vec);
-//  if(bt1 == bt2) cout<<"uguali";
-
+  if(bt1 == bt2) cout<<"uguali";
+  else cout<<"NON UGUALI!";
 }