Circular Linked List

circular_linked_list.cpp

#include <iostream>

using namespace std;

struct Node
{
  int value;
  Node* next;
};

class CircularLinkedList
{
  public:
    CircularLinkedList();
    ~CircularLinkedList();

    void AddNode(Node* newNode);
    void DelNode(Node* delNode);

    void PrintNodes();
  protected:
    Node* head;
};

CircularLinkedList::CircularLinkedList()
{
  this->head = new Node();
  this->head->value = -1;
  this->head->next = this->head;
}

CircularLinkedList::~CircularLinkedList()
{
  Node* curr = this->head->next;

  while (curr != this->head)
  {
    Node* temp = curr->next;
    this->DelNode(curr);
    curr = temp;
  }

  // Delete the head node.
  if (this->head != NULL)
    delete this->head;
}

void CircularLinkedList::AddNode(Node* newNode)
{
  Node* temp = this->head;

  while (temp->next != this->head)
    temp = temp->next;

  Node* next = temp->next;
  newNode->next = temp->next;
  temp->next = newNode;
}

void CircularLinkedList::DelNode(Node* delNode)
{
  Node* prev = this->head;
  Node* curr = prev->next;

  while (curr != this->head && curr != delNode)
  {
    prev = curr;
    curr = curr->next;
  }

  if (curr == this->head)
  {
    cout << "No such node in the list!" << endl;
    return;
  }

  prev->next = curr->next;
  curr->next = NULL;
  delete curr;
}

void CircularLinkedList::PrintNodes()
{
  Node* temp = this->head->next;
  while (temp != this->head)
  {
    cout << temp->value << endl;
    temp = temp->next;
  }
  cout << temp->value << endl;
}

int main(int argc, char* argv[])
{
  CircularLinkedList circularLinkedList;

  Node* newNode_1 = new Node();
  newNode_1->value = 1;
  newNode_1->next = NULL;

  Node* newNode_2 = new Node();
  newNode_2->value = 2;
  newNode_2->next = NULL;

  Node* newNode_3 = new Node();
  newNode_3->value = 3;
  newNode_3->next = NULL;

  circularLinkedList.AddNode(newNode_1);
  circularLinkedList.AddNode(newNode_2);
  circularLinkedList.AddNode(newNode_3);

  circularLinkedList.PrintNodes();

  cout << "After remove 2" << endl;
  circularLinkedList.DelNode(newNode_2);
  circularLinkedList.PrintNodes();

  cout << "After remove 1" << endl;
  circularLinkedList.DelNode(newNode_1);
  circularLinkedList.PrintNodes();

  getchar();
  return 0;
}