I need help being able to make a function that adds an item to the back of a doubly linked list to add an animal to the end of the list in C++ Here's what I got so far with the code #include #include using namespace std;   class node { public:     string data;// Data item     node* next; // Point to next node };   class linkedList { public:          // Variables? (Attributes)     node* headptr;          // Functions (methods)     linkedList()     {         headptr = nullptr;     }          // Add an item to front of list     void addFront(string x)     {         // Declare a pointer variable         node* p;                  // Create a new node, and store its address in p         p = new node;                  // Put x into data field of the new node         // Can also put p -> data = x, same thing.         (*p).data = x;                  // Set next pointer of node to previous front item         (*p).next = headptr;                  //Update the head pointer         headptr = p;     }          // Add an item to the back of the list     void addBack(string x)     {        // Help required here     }                                     // Remove and return front item from list     string popFront()     {         // Step 1: Write down value to return         string output;         output = (*headptr).data;                  // Now, let's remove the front item                  // Write down node location for deletion         node* doomedNode;         doomedNode = headptr;                  // Move headpoint to remove node         headptr = (*headptr).next;                  // Prevent memory lea         delete doomedNode;                  //Step last: Return the value         return output;              }          void printList()     {         // Create pointer initialized to point at first node         node* current;         current = headptr;                  while (current != nullptr)         {             // Print data of current node             cout << (*current).data << endl;                          // Move current to point ot next node             current = (*current).next;         }     }      };     int main()   {     linkedList mylist;          mylist.addFront("Cat");     mylist.addFront("Dog");     mylist.addFront("Lion");     mylist.addFront("Turtle");     mylist.addFront("Tiger");     mylist.addFront("Platypus");          mylist.printList();          cout << "Popping: " << mylist.popFront() << endl;     cout << "Popping: " << mylist.popFront() << endl;     cout << "Popping: " << mylist.popFront() << endl;     cout << "Popping: " << mylist.popFront() << endl;          mylist.addFront("Duck");     mylist.addFront("Goose");          mylist.printList();          // Need help here     mylist.addBack("Deer");     mylist.addBack("Bear");          mylist.printList();       return 0; }