Question

c++ data structures linked list delete node

bool deleteNode(int); pass this method an id to delete. Return true or false to indicate success or failure. Delete the memory the node was using

The algorithm for deleting a Node to a Linked List (general case): ● Begin at the head. ● Compare the id to the current node. ● If search id > current id, stop. ● Detach the current Node ○ current->previous->next = current->next ○ current->next->previous = current->previous ● Deallocate the current Node (no need to detach it’s pointers). ● Return T/F based on successful deletion or not. Note: there are two special cases, delete the head, delete the tail. They are analogous to the add Node special cases. This is left up to the reader to discern

#ifndef LINKEDLIST_H

#define LINKEDLIST_H

#include "data.h"

#include <iostream>   //take this out

using std::cout;

class LinkedList{

    public:

        LinkedList();

        ~LinkedList();

        bool addNode(int, string);

        bool deleteNode(int);

        bool getNode(int, Data*);

        void printList(bool = false);

        int getCount();

        void clearList();

        bool exists(int);

    private:

        Node *head;

};

#endif

----------------------------------------------------------------------------

#ifndef DATA_H

#define DATA_H

#include "string"

using std::string;

struct Data {

    int id;

    string data;

};

struct Node {

    Data data;

    Node *next;

    Node *prev;

};

#endif /* DATA_H */

------------------------------------------------------

bool LinkedList::deleteNode(int id){

    bool success;

    Node *current = head;

    if(current == NULL){

        success = false;

    }

   while(current != NULL){

        if(current -> data.id == id){

            current =  current -> next;

            current = nullptr;

            delete current;

        }   

        success = true;

    }

    return success;

Answer 1

#ifndef LINKEDLIST_H

#define LINKEDLIST_H

#include "data.h"
#ifndef DATA_H

#define DATA_H

#include "string"


#include <iostream>   //take this out

using std::cout;

class LinkedList{

    public:

        LinkedList();

        bool addNode(int, string);

        bool deleteNode(int);

        bool getNode(int, Data*);

        void printList(bool = false);

        int getCount();

        void clearList();

        bool exists(int);

    private:

        Node *head;

};


using std::string;

struct Data {

    int id;

    string data;

};

struct Node {

    Data data;

    Node *next;

    Node *prev;

};



bool LinkedList::deleteNode(int id){

    bool success;

    Node *current = head;
    Node *n=NULL;
    if(current == NULL){

        success = false;

    }

   while(current != NULL){

        if(current -> data.id == id){

            current->data = current->next->data;  
    
             n = current->next;  
  
        // Remove the link of next node  
        current->next = current->next->next;  
  
        // free memory  
        free(n);  

            success = true;
         }
      else{
        current=current->next;
        success=false;
     }

    }

    return success;