//linklist.cpp
//implementation of linklist
#include"linklist.h"
#include"node.h"

linklist::linklist():
  pHead(0)
    {cout << "Making a linklist" << endl;}
  //After debugging, replace with {;}
//*****************************************************

linklist::~linklist()
  {//must get rid of all the links
  Node * pCurrent=pHead;
  cout << "In the linklist destructor." << endl;
    //Remove above line after debugging
  if (pCurrent == 0)
    {
    cout << "Empty list destroyed." << endl;
      //Remove above
    return;
    }
  while (pCurrent != 0)
    {
    pCurrent= pCurrent->getNext();
    delete pHead;
    pHead = pCurrent;
    }
  cout << "The list has been destroyed." << endl;
  //Remove above
  return;
  }

//*****************************************************

void linklist::insert(int  i)
  {
  Node * pCurrent=pHead;
  if (pCurrent == 0)  //empty list
    {
    pHead = new Node(i);  //Creates a
    //Node with the required data
    //and pHead pointing to it.
    return;}
  
  while (pCurrent->getNext() != 0)
    //if list not empty
    //move to the end of the list
    {pCurrent = pCurrent->getNext();}
  
  //pCurrent is now pointing to the last node 
  //of the list
  Node * temp = new Node(i);  //creates
    //a Node with temp pointing to it
  pCurrent->setNext(temp); //attaches new node
    //to the list.
  return;
  }// end insert

//*****************************************************

//notice friend function not member
//so doesn't have linklist::
ostream& operator<<(ostream& out, linklist & li)
  {
  Node * pCurrent=li.pHead;
  if (pCurrent == 0)
    {
    out << "Displaying empty list." << endl;
    return out;
    }
  while (pCurrent != 0)
    {
    out << *pCurrent << endl;  //Prints the Node
      //uses operator<< for the Node class.
    pCurrent= pCurrent->getNext(); 
      //moves on to next node.
    }
  return out;
  }

//*****************************************************

//use -1,000,000 as an end of list marker.
istream& operator>>(istream& in,linklist & li)
  {
  const int eolist=-1000000;
  int m;
  in >> m;
  while (m != eolist)
    {
    li.insert(m);  
    in >> m;
    }
  return in;
  }