diff --git a/librerie/exercise4/binarytree/binarytree.cpp b/librerie/exercise4/binarytree/binarytree.cpp
index 9216be4..028f727 100755
--- a/librerie/exercise4/binarytree/binarytree.cpp
+++ b/librerie/exercise4/binarytree/binarytree.cpp
@@ -61,9 +61,13 @@ const Data& BinaryTree<Data>::Node::Element() const{
 /* ----- end of struct Node ----- */
 
 template <typename Data>
-bool BinaryTree<Data>::operator==(const BinaryTree& toCompare) const noexcept{
-  if(size!=toCompare.size) return false;
-  return(Root() == toCompare.Root());
+bool BinaryTree<Data>::operator==(const BinaryTree& tree) const noexcept{
+  if(size == tree.size){
+    if(size == 0) return true;
+    else return (Root() == tree.Root());
+  }else{
+    return false;
+  }
 }
 
 template <typename Data>
diff --git a/librerie/exercise4/binarytree/lnk/binarytreelnk.cpp b/librerie/exercise4/binarytree/lnk/binarytreelnk.cpp
index 5b49da9..eca6ed9 100755
--- a/librerie/exercise4/binarytree/lnk/binarytreelnk.cpp
+++ b/librerie/exercise4/binarytree/lnk/binarytreelnk.cpp
@@ -140,14 +140,15 @@ BinaryTreeLnk<Data>& BinaryTreeLnk<Data>::operator=(BinaryTreeLnk<Data>&& tree)
   return *this;
 }
 
+/*
+**  operator== and operator!= can be removed from BinaryTreeLnk since they are
+**  inherited from BinaryTree. They're here just for clarity and  because they're
+**  in the template.
+**  Maybe you can make them more optimized here.
+*/
 template <typename Data>
 bool BinaryTreeLnk<Data>::operator==(const BinaryTreeLnk<Data>& tree) const noexcept{
-  if(size == tree.size){
-    if(size == 0) return true;
-    else return (Root() == tree.Root());
-  }else{
-    return false;
-  }
+  return (BinaryTree<Data>::operator==(tree));
 }
 
 template <typename Data>
diff --git a/librerie/exercise4/binarytree/lnk/binarytreelnk.hpp b/librerie/exercise4/binarytree/lnk/binarytreelnk.hpp
index 09d5aa2..85c852e 100755
--- a/librerie/exercise4/binarytree/lnk/binarytreelnk.hpp
+++ b/librerie/exercise4/binarytree/lnk/binarytreelnk.hpp
@@ -15,11 +15,10 @@ protected:
   protected:
 
     using BinaryTree<Data>::Node::data;
-
-  public:
     struct NodeLnk* left = nullptr;
     struct NodeLnk* right = nullptr;
 
+  public:
     struct NodeLnk& operator=(const NodeLnk&); // Copy assignment of abstract types should not be possible.
     struct NodeLnk& operator=(NodeLnk&&) noexcept; // Move assignment of abstract types should not be possible.
     bool IsLeaf() const noexcept override; // (concrete function should not throw exceptions)