I need to understand how a linked list works in this C++ code. I got it from my textbook. Could someone explain in detail what exactly is going on here?
/*The Node Class*/
class Node{
private:
int object;
Node *nextNode;
public:
int get()
{
return object;
}
void set(int object)
{
this-> object=object;
}
Node *getNext()
{
return nextNode;
};
void setNext(Node *nextNode)
{
this->nextNode = nextNode;
};
};
/* The List class */
class List
{
public:
List();
void add (int addObject);
int get();
bool next();
friend void traverse(List list);
friend List addNodes();
private:
int size;
Node * headNode;
Node * currentNode;
Node * lastCurrentNode;
};
/* Constructor */
List::List()
{
headNode = new Node();
headNode->setNext(NULL);
currentNode = NULL;
lastCurrentNode = NULL;
size = 0;
}
/* add() class method */
void List::add (int addObject)
{
Node * newNode = new Node();
newNode->set(addObject);
if( currentNode != NULL )
{
newNode->setNext(currentNode->getNext());
currentNode->setNext( newNode );
lastCurrentNode = currentNode;
currentNode = newNode;
}
else
{
newNode->setNext(NULL);
headNode->setNext(newNode);
lastCurrentNode = headNode;
currentNode = newNode;
}
size ++;
}
/* get() class method */
int List::get()
{
if (currentNode != NULL)
return currentNode->get();
}
/* next() class method */
bool List::next()
{
if (currentNode == NULL) return false;
lastCurrentNode = currentNode;
currentNode = currentNode->getNext();
if (currentNode == NULL || size == 0)
return false;
else
return true;
}
/* Friend function to traverse linked list */
void traverse(List list)
{
Node* savedCurrentNode = list.currentNode;
list.currentNode = list.headNode;
for(int i = 1; list.next(); i++)
{
cout<<"\n Element "<<i<<" "<<list.get();
}
list.currentNode = savedCurrentNode;
}
/* Friend function to add Nodes into the list */
List addNodes()
{
List list;
list.add(2);
list.add(8);
list.add(7);
list.add(1);
cout<<"\n List size = "<<list.size<<"\n";
return list;
}
main()
{
List list = addNodes();
traverse(list);
system("pause");
}