// CS2310 Excise 15
// Chapter 16
//
// Name ___________________________ SSN _______________________
//
// p960 - 1
// To the SortedList2 class, add a value-returning 
// member function named Length that counts and returns
// the number of nodes in a list.
//
//  IMPLEMENTATION FILE  DYNAMIC-LINKED SORTED LIST
//  ( slist2.cpp )

#include <iostream>
#include "slist2.h"

using namespace std;

bool SortedList2::IsEmpty ( ) const {
	return (head == NULL);
}

void SortedList2::Print ( ) const {
	NodePtr ptr = head;

	cout << "The elements in the list is:" << endl;
	while (ptr != NULL) {
		printf("%6d", ptr->item);
		ptr = ptr->link;
	}
	cout << endl;
}

void SortedList2::InsertTop ( /* in */  ItemType  item ) {
	NodePtr  location;

	location = new  NodeType;
	location->item = item;
	location->link = head;
	head = location;
}

void SortedList2::DeleteTop ( /* out  */  ItemType&  item ) {
	NodePtr  tempPtr;
	
	item = head->item;
	tempPtr = head;
	head = head->link;
	delete  tempPtr;
}
	
SortedList2::SortedList2 ( ) {
	// Constructor
	// Post:	  head == NULL
	head = NULL;
}

SortedList2::~SortedList2 ( )
	// Destructor
	// Post:  All linked nodes deallocated 
{
	ItemType  temp ;
					// keep deleting top node
	while  ( !IsEmpty() )
		DeleteTop ( temp );
}

int SortedList2::Length(void)
	  // POST: Return the number of elements in
	  //	the list.
{
	NodePtr ptr = head;
	int count = 0;

	// Write the omitted code here:
	// Beginning from head, follow the link until
	// reach the end of the list. Count during the
	// tracing.

	return count;
}

int main() {
	SortedList2 slist;
	ItemType item;
	int i;

	for (i=0; i<5; i++) 
		slist.InsertTop(i);
	slist.Print();
	cout << "The number of elements in the list is: "
		<< slist.Length() << endl << endl;

	for (i=0; i<3; i++) 
		slist.InsertTop(i+5);
	slist.Print();
	cout << "The number of elements in the list is: "
		<< slist.Length() << endl << endl;

	for (i=0; i<4; i++) 
		slist.DeleteTop(item);
	slist.Print();
	cout << "The number of elements in the list is: "
		<< slist.Length() << endl << endl;

	return 0;
}