This C++ CODE has many functions that needs to be testedpiece by piece
For example, you going to display each function with [ ]and a , separating each piece of data, like so:[1,2,3,4]?
results must be copied and pasted as commnets at thebottom of this file
this is the code:
#include
#include
#include //for NULL
using namespace std;
class List
{
  private:
     struct Node
     {
        int data;
        Node*next;
        Node(intdata): data(data), next(NULL){}
     };
     typedef struct Node*Nodeptr;
     Nodeptr first;
     Nodeptr last;
     int size;
  public:
     /**Constructors */
     List()
     {
           first = NULL;
           last = NULL;
           size = 0;
     }
     /* Destructors*/
     ~List()
     {
        Nodeptrcursor = first;
        Nodeptrtemp;
        while (cursor!= NULL)
        {
           temp = cursor -> next;
           delete cursor;
           cursor = temp;
        }
     }
     //ANOTHER WAY TO WRITE
     //AND YES IT WORKS
           /* last = NULL;
           while(first != NULL)
           {
              Nodeptr temp = first;
              first = first->next;
              delete temp;
           } /*
     /**Accessors*/
     int getFirst()
     {
        if(isEmpty())
           return 0;
        returnfirst->data;
     }
     int getLast()
     {
        if(isEmpty())
           return 0;
        returnlast->data;
     }
     bool isEmpty()
     {
        if(first ==NULL)
        {
           return true;
        }
           else return false;
     }
     int getSize()
     {
        return size;// return the size of the list
     }
     /**Manipulation Procedures*/
     void removeLast()
     {
        if(isEmpty()== false) // if list is not empty
        {
           if(first -> next == NULL) // list has only 1node
           {
              delete first;
              first = NULL;
              last = NULL;
           }
           else
           {
              Nodeptr temp = first;
              while(temp -> next !=last)
              {
                 temp =temp -> next; //advance the pointer
              }
              delete last; //free thememory for the original last node
              temp -> next = NULL; //solast->next is not pointing at freed memory
              last = temp;
              size -- ; // decreasingsize
           }
        }
     }
     void removeFirst()
     {
        if (size ==0)
        {
           cout << \"removeFirst: List is empty. nodata to remove.\" << endl;
        }
        else if (size== 1)
        {
           delete first;
           first = last = NULL;
           size = 0;
        }
        else
        {
           Nodeptr temp = first; //store pointer to firstso we dont lose access
           first = first -> next; //advance thepointer
           delete temp; //free the memory for the originalfirst node
           size--;
        }
     }
     /*{
        if(isEmpty()== false)
        {
           if(first -> next == NULL)// list has only onenode
           {
              first = NULL;
              last = NULL;
              delete first;
           }
           else
           {
              Nodeptr temp = first;
              first = first -> next;
              delete temp;
           }
           size = size - 1;
        }
     } */
     void insertLast(int data)
     {
        if(first ==NULL)
        {
           first = new Node(data);
           last = first;
        }
        else
        {
           last -> next = new Node(data);
           last = last -> next;
        }
        size++;
     }
     void insertFirst(int data)
     {
        if (size ==0)
        {
           first = new Node(data);
           last = first;
        }
        else
        {
           Nodeptr N = new Node(data);
           N -> next = first;
           first = N;
        }
        size ++;
        /*if(first ==NULL)
        {
           first = new Node(data);
           last = first;
        }
        else
        {
           Nodeptr temp = new Node(data);
           temp -> next = first;
           first = temp;
        }
        size++;*/
     }
     /**Additional ListOperations*/
     void printList()
     {
        Nodeptr temp= first;
        while(temp !=NULL)
        {
           cout << temp -> data <<\" \";
           temp = temp -> next;
        }
        cout <     }
     };
int main()
{
  List list;
  list.insertFirst(2);
  list.insertFirst(4);
  list.printList();
  list.removeFirst();
  list.printList();
  cout<<\"Size:\"<  return 0;
}
