#include <iostream.h>
#include "CPstring.h"


// for cps 100e, fall 1996
// based on an assignment from cps 100e, fall 1995,
// but declarations changed form single to doubly linked lists

struct StudentNode
{
   string first;
   string last;
   StudentNode * next;
   StudentNode * prev;

   StudentNode(const string & fname, const string & lname, 
               StudentNode * after = NULL, StudentNode * before = NULL)
   {
       first = fname;
       last = lname;
       next = after;
       prev = before;
   }

   void Print()
   {
     cout << "\t" << first << " " << last << endl;
   }
};


struct SectionNode
{
   int section;
   SectionNode * next;
   StudentNode * list;

   SectionNode(int sec, SectionNode * link = NULL, StudentNode * sptr = NULL)
   {
      section = sec;
      next = link;
      list = sptr;
   }
     
};

void EnterStudent(SectionNode * & current, int sec,
		  const string & first, const string & last)
// postcondition: creates a new SectionNode if sec is a new section number
//                enters the student in the list corresponding to sec
{
    if (current != NULL)
    {
	if (current->section == sec)   // add to front of list
	{
	    StudentNode * header = current->list;
	    header->next = new StudentNode(first,last,header->next,header);
	    header->next->next->prev = header->next;		
	}
	else
	{
	    EnterStudent(current->next, sec, first, last);
	}
    }
    else
    {
	// add a new node with a header node
	current = new SectionNode(sec);
	current->list = new StudentNode("dummy","header");
	current->list->next = new StudentNode(first,last,0,current->list);
    }
}

void CreateList(SectionNode * & head)
// postcondition: creates a list of sections, each section list contains
//                a list of students in that section     
{
    string first, last;
    int section;
     
    while (cin >> section >> last >> first)
    {
	EnterStudent(head, section, first, last);
    }
}


void PrintSection(StudentNode * current)
// precondition: current points to a list of students in a particular section.
// postcondition: prints the list of the students in this section.
{
    current->Print();
    PrintSection(current->next);
}

void PrintList(SectionNode * head)
// postcondition: prints each section number followed by a list of the students
//                in that section.
{
    if (head != NULL)
    {
	cout << "Section " << head->section << endl;
	PrintSection(head->list->next);  // skip header to print
	PrintList(head->next);
    }
}

StudentNode * FindStudent(SectionNode * secPtr,
			const string & first, const string & last)
// postcondition: returns  pointer to node containing first/last
//                returns NULL if not found in section
{
    StudentNode * current = secPtr->list;
    while (current != 0)
    {
	if (current->first == first && current->last == last)
	{
	    return current;
	}
	current = current->next;
    }
    return 0;
}

int WhichSection(SectionNode * head,
		 const string & first, const string & last)
// postcondition: returns the first section number the name appears in     
//                returns 0 if the name is not in any section
{
   cout << "WhichSection not implemented" << endl;
   return 0;
}


void FindAll(SectionNode * head, const string & first)
// postcondition: prints all sections and full names of people with
//                first name == first
{
   cout << "FindAll not implemented" << endl;
}


void Remove(SectionNode * head,
	    const string & first, const string & last)
// postcondition: removes (only first occurence) of a name found in list
//                pointed to by head
{
   cout << "Remove not implemented" << endl;
}

main()
// test all routines
{
  SectionNode * head = NULL;
  cout << "Create list " << endl;
  CreateList(head);
  PrintList(head);

  cout << "Peter Teichman is in Section " << 
        WhichSection(head,"PETER","TEICHMAN") << endl;

  cout << "Find all occurences of Matt" << endl;
  FindAll(head,"MATT");


  cout << "Remove Ross Baker " << endl;
  Remove(head, "ROSS", "BAKER");
  
  cout << "Remove Emma Wong" << endl;
  Remove(head,"Emma", "Wong");

  // PrintList(head);
}