Question

HELP with c++ code..

Having trouble with this method.

bool List::remove(int index){
   //remove the Planet object at index, decreasing the size of the Vector by 1.
   //return true on successful deletion or false if the index is out of bounds

}

Here is the header file..

#ifndef LIST_H
#define LIST_H
#include "Planet.h"
#include <iostream>
class Node
{
   friend class List; //allow list class to access private fields
   //https://www.geeksforgeeks.org/friend-class-function-cpp/
   private:
       Planet *planet;
       Node *next;
       Node *prev;
   public:
       Planet* getPlanet(){return this->planet;}
       Node(Planet * p);
      
};

class List{
   private:
       Node *head;
       Node *tail;
   public:
       List();
       ~List();
       void insert(int index, Planet * p);
       Planet * read(int index);
       bool remove(int index);
       unsigned size();
};

#endif

Answer 1

CODE

bool List::remove(int index)

{

/* if list in NULL or invalid position is given */

if (*head == NULL || index < 0)

return false;

struct Node* current = *head;

int i;

for (int i = 1; current != NULL && i < index; i++)

current = current->next;

/* if 'n' is greater than the number of nodes

in the doubly linked list */

if (current == NULL)

return false;

/* If node to be deleted is head node */

if (*head == current)

*head = current->next;

/* Change next only if node to be deleted is NOT

the last node */

if (current->next != NULL)

current->next->prev = current->prev;

/* Change prev only if node to be deleted is NOT

the first node */

if (current->prev != NULL)

current->prev->next = current->next;

return true;

}