Doubly-Linked-List (creare, adaugare dupa si inainte, stergere, afisare si reverse)

Doubly-Linked-List

#include <iostream>

class DoublyLinkedList {

	  struct Node {
	  	  int data;
	  	  struct Node *next;
	  	  struct Node *prev;
	  	  Node(int d): data(d), next(nullptr), prev(nullptr){}	  	  
	  };

	  struct Node *head = nullptr;   

	  public:

     //4--->>3--->2 -->1 
	  	//push_front()
	  	//push_back()
	  void addToLinkedList(int val) {
         
           Node *newNode = new Node( val );

           if( head == nullptr ) {

           	  head = newNode;

           } else {
         
              newNode->next = head;

              head->prev = newNode;

              head = newNode;
           }
	  }	

      //HEAD -> 1 2 3 4 X 5 6 7 8
      //              c
	  void addAfterNode(int afterNode, int val) {

           Node *c = head;       


           //ne pozitionam pe nodul dupa care vreau sa inserez noul NODE
           while(c != nullptr && c->data != afterNode) c = c->next;

           if(c == nullptr) {
           	  std::cout<<"Nodul cu informatie afternode nu exista in lista";
           	  return;
           } 

           //am creat nodul nou
           // next(nullptr)
           // prev(nullptr)
           Node *newNode = new Node( val );


           newNode->next = c->next;

           newNode->prev = c;

           if(c->next != nullptr) {

           	  c->next->prev = newNode;
           }

           c->next = newNode;
	  }

	  //1 --> 2 --> 3 --> ,,,,, --->N
	  //next

	  void display() {

	  	   Node*c = head;

	  	   while(c != nullptr) {

	  	   	  std::cout<<c->data<<" ";

	  	   	  if(c->next != nullptr) std::cout<< " <-> "; 

	  	   	  c = c->next;
	  	   }

	  	   std::cout<<std::endl;
	  }

      //1 --> 2 --> 3 --> ,,,,, --->N
      //1 <--> 2 <--> 3 <--> ,,,,, <--->N
	  void displayReverse() {

	  	   Node *c = head;

	  	   if(c == nullptr) {

	  	   	  return;
	  	   }

	  	   while(c->next != nullptr) {
	  	   	   c = c->next; // ma duc pana la capat
	  	   }

	  	   while(c !=nullptr) {

	  	   	  std::cout<<c->data<<" ";

	  	   	  if(c->prev != nullptr) std::cout<<" <-->";

	  	   	  c = c ->prev;//ma deplasez pe prev
	  	   }
	  }

      /*
              1 2 3 X 4 5 6 7
       newNode
      */
	  void addBeforeNode(int beforeNode, int val) {
 
            Node*newNode = new Node( val );


             if(head != nullptr && head->data == beforeNode) {

             	 newNode->next = head;

             	 head->prev = newNode;

             	 head = newNode;

             	 return;
             }

             Node *c = head;

             while(c != nullptr && c->next != nullptr && c->next->data != beforeNode) {

             	  c = c->next;
             }

             if( c == nullptr || c->next == nullptr) {
             	std::cout<<"Nodul nu a fost gasit!"<<std::endl;
             	return;
             }                

             //1 2 3 4 5 X 22 6 7 8
             //        c 
             newNode->next = c->next;

             newNode->prev = c;

             if(c->next != nullptr) {
             	c->next->prev = newNode;
             }

             c->next = newNode; //(X)
	  }

	  // 1 2 3 4 5 6 7
	  //   head

	  void removeNode(int delNode) {

           if(head ==nullptr) {
           	  std::cout<<"Lista este Goala";
           	  return;
           }  

           //cazul in care nodul de sters este chiar HEAD
           if(head->data == delNode) {

           	  Node *toRemove = head;//luam adresa capului listei 

           	  head = head->next; 

           	  if(head != nullptr) {
           	  	  head->prev = nullptr;
           	  }

           	  delete toRemove;

           	  return;
           }

           //1 2 3 4 5 toRemove 6 7 8 9
           //        c
           /*
           step 1: te pozitionezi pe nodul de dinaintea nodului de sters =>C
           */
           Node *c = head;

           while(c->next != nullptr && c->next->data != delNode) {
           	     c = c->next;
           }

          //testam daca exista in lista
           if(c->next == nullptr) {
           	  std::cout<<"Nodul cu valoare delNode nu exista in Doubly Linked List";
           	  return;
           }

           //daca exista nodul de sters
           Node *nodeToRemove = c->next; //retinem adresa nodului de sters
           //c->next = adresa nodului de STERS
           c->next = nodeToRemove->next;

           if(nodeToRemove->next != nullptr) {

           	  nodeToRemove->next->prev = c;
           }

           delete nodeToRemove;//stergi nodul din memoria HEAP           

	  }

};


int main(int argc, char const *argv[])
{
	DoublyLinkedList list; 

	int arr[] =  {1, 22, 3, 4, 57, 10 , 101};

 
    for(int val: arr) { 

	    list.addToLinkedList(val);
	}
	
	list.display();   

	//std::cout<<"REVERSE Cu deplasare pe PREV:\n";

		//list.displayReverse();   

    std::cout<<"Adaugare dupa Node:\n";

	list.addAfterNode(57,58);

	list.display();   

    std::cout<<"Adaugare inainte Node:\n";
	list.addBeforeNode(57,56);

    list.display();   

    std::cout<<"Stergere Node HEAD:\n";
    list.removeNode(101);
	list.display();   

	std::cout<<"Stergere Node din interiorul Listei:\n";
    list.removeNode(4);
	list.display();   
	
	return 0;
}