Project 2 done before changing the Insert

#include "Set.h"

void Set::initializeEmptySet()
{
	m_size = 0;

	m_head = new Node;
	m_tail = m_head;
	m_head->m_next = nullptr;
	m_head->m_prev = nullptr;
}

Set::Set()
{
	initializeEmptySet();
}

// Before we can actually insert the node, we need to implement the insert before function

void Set::insertNewHead(const ItemType& value)
{
	Node* new_head = new Node;
	new_head->m_value = value;

	m_head->m_prev = new_head;
	new_head->m_prev = nullptr;
	new_head->m_next = m_head;
	m_head = new_head;

	m_size++;
}

void Set::insertNewTail(const ItemType& value)
{
	if (m_head == nullptr)
		insertNewHead(value);

	else
	{
		Node* traversal_node = m_head;
		while (traversal_node->m_next != nullptr)
		{
			traversal_node = traversal_node->m_next;
		}

		Node* new_tail = new Node;
		traversal_node->m_next = new_tail;
		new_tail->m_value = value;
		new_tail->m_prev = traversal_node;
		new_tail->m_next = nullptr;
		m_tail = new_tail;
	}

	m_size++;
}

void Set::insertBefore(Node* p, const ItemType& value)
{
	//Create a new node

	Node* new_pointer = new Node;
	new_pointer->m_value = value;

	if (p == m_head)
	{
		insertNewHead(value);
		return;
	}

	// Set the new pointer's previous pointer equal to p's previous pointer
	// Then set the new pointer's next pointer equal to p
	new_pointer->m_prev = p->m_prev;
	new_pointer->m_next = p;

	// We must now make the previous nodes point to this new node
	// Then we must make the next node have its previous point to this node.
	new_pointer->m_prev->m_next = new_pointer;
	new_pointer->m_next->m_prev = new_pointer;

	m_size++;
}

// I have no idea how to write these function parameters
// Why is there a Set:: before declaring a node pointer?
// Is it because we can only define what a node pointer is after defining it's from the Set class?
Set::Node* Set::findClosestLocation(const ItemType& value) const
{
	Node* p = m_head;

	while (p->m_next != nullptr && p->m_value < value)
	{
		p = p->m_next;
	}

	return p;
}

bool Set::insert(const ItemType& value)
{
	// First we will check the head
	if (value == m_head->m_value)
		return false;

	else if (m_size == 0 || value < m_head->m_value)
	{
		insertNewHead(value);
		if (m_size == 1)
		{
			m_tail = m_head;
		}
		return true;
	}

	// Then we will check the tail
	else if (value == m_tail->m_value)
		return false;

	else if (value > m_tail->m_value)
	{
		insertNewTail(value);
		m_size++;
		return true;
	}

	// Finally, we will try to insert in the middle of the list
	else
	{
		Node* closestNode = findClosestLocation(value);
		if (closestNode->m_value == value)
			return false;
		insertBefore(closestNode, value);
		return true;
	}
}

void Set::actualErase(Node* p)
{
	if (m_size == 1)
	{
		p->m_next = p->m_prev = nullptr;
		m_head = m_tail = nullptr;
	}

	else if (p == m_head)
	{
		m_head->m_next = m_head;

		p->m_next->m_prev = nullptr;
	}

	else if (p == m_tail)
	{
		m_tail->m_prev = m_tail;

		p->m_prev->m_next = nullptr;
	}

	else
	{
		p->m_prev->m_next = p->m_next;
		p->m_next->m_prev = p->m_prev;
	}

	delete p;
	m_size--;
}

bool Set::erase(const ItemType& value)
{
	if (m_head->m_value == value || m_tail->m_value == value)
		actualErase(value);

	else
	{

	}

}