Fix binary tree

include/blt/std/binary_tree.h

@@ -92,9 +92,11 @@ namespace blt {
                         nodeStack.push(current);
                         current = current->left;
                     }
-                    current = nodeStack.front();
+                    // take the parent node of the left most subtree
+                    current = nodeStack.top();
                     nodeStack.pop();
                     nodes.push_back(current);
+                    // traverse its right tree
                     current = current->right;
                 }
                 
@@ -111,20 +113,39 @@ namespace blt {
             }
             
             [[nodiscard]] BST_node* search(const T& element) const {
-                search(nullptr, element);
+                return search(nullptr, element);
             }
             
             void remove(const T& element) {
                 BST_node* parent = nullptr;
-                auto elementNode = search(parent, element);
+                BST_node* elementNode = search(parent, element);
+                
+                BST_node*& parentChildSide = parent->left;
+                if (parent->right == elementNode)
+                    parentChildSide = parent->right;
+    
+                if (elementNode->left != nullptr && elementNode->right != nullptr){
+                    parentChildSide = nullptr;
                     // reconstruct subtree. More efficient way of doing this... TODO
                     std::vector<BST_node*> subNodes = inOrderTraverse(elementNode);
                     for (auto* node : subNodes){
-                    if (node != elementNode)
+                        // insert will create a new node, we must delete old one to prevent memory leaks
+                        if (node != elementNode) {
                             insert(parent, node->payload);
+                            delete(node);
                         }
                     }
     
+                } else {
+                    parentChildSide = elementNode->left != nullptr ? elementNode->left : elementNode->right;
+                }
+                delete(elementNode);
+            }
+        
+            std::vector<BST_node*> inOrderTraverse(){
+                return inOrderTraverse(m_root);
+            }
+            
             ~node_binary_search_tree() {
                 delete (m_root);
             }

include/blt/std/queue.h

@@ -61,7 +61,7 @@ namespace blt {
              * Warning does not contain runtime error checking!
              * @return the element at the "front" of the queue.
              */
-            [[nodiscard]] const T& front() const {
+            [[nodiscard]] const T& top() const {
                 return m_data[m_insertIndex - 1];
             }