From 1644e4064123b5fc9f66d60d8c0717e36aef23f8 Mon Sep 17 00:00:00 2001
From: SleepiCaffeine <depressed.machiato@gmail.com>
Date: Tue, 20 Jun 2023 19:19:00 +0300
Subject: [PATCH] Fixed bugs in double_node and dl_list classes

---
 Data Structures/dl_list.hpp     | 38 +++++++++++++++++++++++++++------
 Data Structures/double_node.hpp | 10 ++-------
 2 files changed, 34 insertions(+), 14 deletions(-)

diff --git a/Data Structures/dl_list.hpp b/Data Structures/dl_list.hpp
index d0f59d2..32481a9 100644
--- a/Data Structures/dl_list.hpp	
+++ b/Data Structures/dl_list.hpp	
@@ -13,6 +13,7 @@
 #include "double_node.hpp"
 #include <cstddef>
 #include <stdexcept>
+#include <iostream>
 
 /*!
  * @class dl_list
@@ -260,14 +261,18 @@ class dl_list {
      * @return Length of LL
      * @see size()
      */
-    unsigned int length() const {return len;}
+    unsigned int length() {
+        update_len();
+        return len;}
 
     /**
      * Returns the length of the sl list
      * @return Length of LL
      * @see length()
      */
-    unsigned int size() const {return len;}
+    unsigned int size() {
+        update_len();
+        return len;}
 
     /**
      * Updates the length of the sl_list (Mainly kept to avoid bugs, will later implement other features to avoid using this)
@@ -332,6 +337,15 @@ double_node<T>* dl_list<T>::push_front(T dt) {
         ++len;
         return head;
     }
+
+    if (len == 1) {
+        tail = head;
+        head = new double_node<T>(dt);
+        head->set_next(tail);
+        tail->set_prev(head);
+        ++len;
+        return head;
+    }
     // Create a new head object with the provided data and pointing to the head itself
     head = new double_node<T>(head, dt);
     ++len;
@@ -342,16 +356,26 @@ template <typename T>
 double_node<T>* dl_list<T>::push_front(double_node<T>* const nd) {
     // If the list has a length of 0, create a node for the head, and set the tail to nullptr
     if (!len) {
-        head = new double_node<int>(*nd);
+        head = new double_node<T>(*nd);
         tail = nullptr;
         ++len;
         return head;
     }
 
+    if (len == 1) {
+        tail = head;
+        head = new double_node<T>(*nd);
+        head->set_next(tail);
+        tail->set_prev(head);
+        ++len;
+        return head;
+    }
+
     // Swap head and provided node
-    auto oldHead = new double_node<T>(head->get_next(), nd, head->get_data());
+    auto oldHead = new double_node<T>(*head);
+    oldHead->set_prev(nd);
     nd->set_next(oldHead);
-    head = nd;
+    head = new double_node<T>(*nd);
 
     ++len;
     return head;
@@ -411,7 +435,9 @@ double_node<T>* dl_list<T>::push_back(double_node<T>* const nd) {
     }
 
     double_node<T>* currNode = head;
-    double_node<T>* oldTail = new double_node<T>(nd, tail->get_prev(), tail->get_data());
+    double_node<T>* oldTail = new double_node<T>(*tail);
+    oldTail->set_next(nd);
+
     nd->set_prev(oldTail);
     tail = nd;
 
diff --git a/Data Structures/double_node.hpp b/Data Structures/double_node.hpp
index c23bf31..6ebd2c9 100644
--- a/Data Structures/double_node.hpp	
+++ b/Data Structures/double_node.hpp	
@@ -192,14 +192,8 @@ class double_node {
 };
 
 template <typename T>
-double_node<T>::double_node(const double_node<T>& nd) {
-    next = new double_node<T>();
-    prev = new double_node<T>();
-
-    next = nd.get_next();
-    prev = nd.get_prev();
-    data = nd.get_data();
-}
+double_node<T>::double_node(const double_node<T>& nd)
+    : next{nd.get_next()}, prev{nd.get_prev()}, data{nd.get_data()} { }
 
 template <typename T>
 void double_node<T>::set_prev(double_node<T>* const nd) {