#include <stdio.h>
#include <stdlib.h>
#include <assert.h>
#include "ClassList.h"


StudentNode* head;
StudentNode* tail;

int numStudents;



void InitializeList() {
    head = NULL;
    tail = NULL;
    numStudents = 0;
}

int GetCount() {
    return numStudents;
}


StudentNode* CreateNode (Student* aStudent) {
    StudentNode* temp = (StudentNode*) malloc (sizeof (StudentNode));
    temp->data = aStudent;
    temp->next = NULL;
    return temp;
}

void DestroyNode (StudentNode* aNode) {
    DestroyStudent (aNode->data);
    free (aNode);
}

void EmptyList() {
    StudentNode* currNode;
    StudentNode* nextNode;

    currNode = head;
    while (currNode != NULL) {
        nextNode = currNode->next;
        DestroyNode (currNode);
        currNode = nextNode;
    }
    InitializeList();
}


void Prepend (Student* aStudent) {
    StudentNode* newNode = CreateNode (aStudent);

    if (head == NULL) {     /*  List is empty  */
        head = newNode;
        tail = newNode;
    } else {
        newNode->next = head;
        head = newNode;
    }
    ++numStudents;
}

void Append (Student* aStudent) {
    StudentNode* newNode = CreateNode (aStudent);

    if (head == NULL) {    /*  List is empty  */
        head = newNode;
        tail = newNode;
    } else {
        tail->next = newNode;
        tail = newNode;
    }
    ++numStudents;
}


void Insert (int position, Student* aStudent) {

    /*  Variable declarations go here  */

  
    /*  This assert statement checks the pre-condition.  */
    assert (position > 0 && position <= numStudents + 1);

    /*  Add the statements to do the insert here.  */
    /*  Don't forget to increment numStudents.     */

}

void Delete (int position) {

    /*  Complete this function.                    */
    /*  Don't forget to check the pre-condition,   */
    /*    destroy the deleted node, and decrement  */
    /*    numStudents.                             */
   
}


int Find (long idNum) {

    /*  Complete this function  */

}

void PrintList() {
    StudentNode* currNode;

    currNode = head;
    while (currNode != NULL) {
        PrintStudent (currNode->data);
        currNode = currNode->next;
    }
}

void DumpList() {

    /*  Complete this function.                          */
    /*  Hint:  Use %p with printf() to print addresses.  */

}