/*
 * This is a solution to the LinkedList.cpp program you were asked to write for this week. Note
 * that is doesn't contain as many comments as usual because many were already provided in the 
 * skeleton file, so only some implementation issues will be pointed out here.
 *
 */
 
#include<iostream>
using namespace std;
	
class LinkedList {
 
private:	
	class Node {
		public:
			char data;
			Node *next;
	};
	Node *first;

public:
	LinkedList();
	void insert(char dat);
	void print();
	~LinkedList();
	
};

//Main program tests the class by inserting a few values and then printing out the list.
int main() {

	LinkedList list;
	list.insert('a');
	list.insert('b');
	list.insert('b');
	list.print();
	return 0;
}

LinkedList::LinkedList() {
	first = NULL;
}

//Insert method creates a new node for every data value, even if it is already in the list. The 
//insertion algorithm should be familiar from data strucures.
void LinkedList::insert(char dat) {

	Node *newNode = new Node;
	newNode->data = dat;
	newNode->next = NULL;

	if(first == NULL) {
		first = newNode;
	}
	else{
		Node *current;
		current = first;
		
		while(current->next != NULL) {
			current = current->next;
		}
		current->next = newNode;
	}
}

//Print out the list by looping through it, unless the list is empty in which case we tell the user
//that. Again, the algorithm should be familiar from data structures.
void LinkedList::print(){
	Node *current;
	current = first;
	
	if(current == NULL) {
		cout << "There are no nodes in the list.";
	}
	else {	
		while(current != NULL) {
			cout << current->data << endl;
			current = current->next;
		}	
	}
}

//The class destructor. While it looks simple it is actually surprisingly tricky to write. The key
//is moving forward through the list and updating first.
LinkedList::~LinkedList() {

	Node *current;
	
	while(first != NULL) {
		//Set curent equal to the first pointer. 
		current = first;
		//Reset first to point to the next node in the list.
		first = first->next;
		//Delete the first node in the list so that we don't leak memory, and repeat.
		delete current;
	}
}