#include "list.h"

using namespace std;


// Constructor for Class List
List::List()
{last = first = 0;
 cout << "allocated List " << this << endl;
}

List::~List()
{cout << "deallocated List " << this << endl;}

void List::Printout() // Printing out the contents of a List
{
    ListNode  *ptr;
    ptr = first;
    while(ptr)
     { cout << ptr->GetData() << " Listode " << ptr << endl;
       ptr = ptr->GetNext();
     }
    return;
}

void List::Readin()  // Reading in the contents of a List
{ int contents;
  cout << "Input a List. one element per line and ending with a line with just a zero" << endl;
  cin >> contents;
  while (contents)
   {this->InsertSorted(contents);
    cin >> contents;   
   }
}

void List::InsertAfterNode(ListNode *p, int x) // Insert a ListNode after
                                           // certain ListNode in a List
{
    ListNode *t = new ListNode(x); // create and initialize new node
    // insert after p
    t->SetNext( p->GetNext() );
    p->SetNext( t );
    if (last == p) last=t;
}

void List::InsertFront(int x) // Insert a ListNode at the
                              // beginning of a List
{
    ListNode *t = new ListNode(x); // create and initialize new node
    t->SetNext( first );
    if (last == 0) last = t;
    first = t;
}

void List::InsertSorted(int x) { // Insert a ListNode with data value x
    ListNode *p = first;
    if (p == 0) {InsertFront(x); return;}
    if (x == p->GetData()) return;
    if (x < p->GetData()) {InsertFront(x); return;}
    while (p->GetNext())
       { 
         if (p->GetNext()->GetData() == x) return;
         if (p->GetNext()->GetData() > x) {InsertAfterNode(p,x); return;}
         p = p->GetNext();
       }
    InsertAfterNode(p,x);
}

void List::Erase() {
   ListNode *ptr, *tempptr;
   ptr = first;
   while(ptr)
     {
       tempptr=ptr->GetNext();
       delete(ptr);
       ptr=tempptr;
     }
   last = first = 0;
}