// filename: llist.cpp

#include <iostream>
using namespace std;

#include "node.h"
#include "llist.h"


LinkedList::LinkedList()
{
  header = NULL;  elementCount = 0;
}

bool LinkedList::isEmpty() const
{
  return (header == NULL); // or (elementCount == 0)
}

// size() -- returns the number of elements stored in this list.
int LinkedList::size() const
{
  return elementCount;
}

Node* LinkedList::find(int x) const
{
  Node* ptr;

  for (ptr = header; ptr != NULL; ptr = ptr->next)
  {
    if (ptr->element == x)
      return ptr;  // early exit
  }

  return ptr;
}

void LinkedList::insertFront(int x)
{
  // One line would do, because even if the list is empty
  // (i.e., header == NULL), that value is good for the
  // value for the new node.
  header = new Node(x, header);
  elementCount++;
}

void LinkedList::insertAfter(int x, Node* p)
{
  if (p != NULL)
  {
    p->next = new Node(x, p->next);
    elementCount++;
  }
}

void LinkedList::removeAfter(Node* p)
{
  if (p != NULL)
  {
    Node* temp = p->next;

    if (temp == NULL)
    {
      cout << "ERROR: no node after p\n";
      return;
    }
    else
    {
      p->next = temp->next;
      delete temp;
      elementCount--;
    }
  }
}