#include <iostream>
#include <fstream>
#include <string>
#include <sstream>
 
using namespace std;
 
class Node{
public:
	int coef;
	int exp;
	Node* next;
 
	Node(){
		coef = 0;
		exp = 0;
		next = NULL;
	}//default constructor
 
	Node(int c, int e){
			if(e < 0){
				cout << "Exponent is negative" << endl;
				exit(1);
			}//if check if exponent is < 0
		coef = c;
		exp = e;
		next = NULL;
	}//2 param constructor
 
	~Node(){
		delete next;
	}//destructor
 
};
 
class LinkedList{
public:
	Node* start;
 
	LinkedList(){
		start = NULL;
	}//default constructor
 
	LinkedList(const LinkedList& l){
		Node* temp = l.start;
		if(temp == NULL){
			cout << "List is empty";
			exit(1);
		}//if
		else{
			while(temp != NULL){
				this->add(temp);
				temp = temp->next;
			}//while
 
		}//else
	}//copy constructor
 
	~LinkedList(){
		delete start;
	}//destructor
 
 
	void add(Node*& n){
		if(start == NULL){
			start = n;
			start->next = NULL;
		}//if
		else{
			Node* temp = start;
				if(n->exp >= temp->exp){
					n->next = temp;
					start = n;
					return;
				}//if
 
				else{
					while(temp!= NULL){
						if(n->exp >= temp->next->exp){
							n->next = temp->next;
							temp->next = n;
							return;
						}//if
						temp = temp->next;
					}//while
 
				}//else
		}//else
	}//add
 
	void display(){
		Node* temp = start;
			do{
				if(temp == NULL){
					cout << "List is empty" << endl;
					return;
				}//if
				else{
					cout << temp->coef << " ";
					cout << temp->exp << " ";
				}//else
				temp = temp->next;
			}//do 
			while(temp != NULL);//while
		cout << endl;
	}//display
 
 
 
	void operationAdd(){
		Node* temp = start;
 
			//if empty list or only 1 node
			if(temp == NULL || temp->next == NULL)
				return;
 
		while(temp != NULL){
			if(temp->next == NULL)
				break;
			if(temp->exp == temp->next->exp){
					temp->coef += temp->next->coef;//add the coef
				Node* temp1 = temp->next;//temp1 holding it
				temp->next = temp1->next;//set temp next = to temp->next->next
			}//if
			else{
				if(temp->next == NULL)
					break;
				temp = temp->next;//if not keep going
			}//else
		}//while
	}//operationAdd
 
 
 
 
 
};
 
 
 
int main()
{
	LinkedList* current = new LinkedList;
	string line;
	int repeat = 0;
 
	ifstream myfile("input.txt");
	if(myfile.is_open()){
		while(!myfile.eof()){
			getline(myfile, line);
			repeat++;
			cout << "\nLine: " << repeat << " \n"; 
			cout << line << endl;
			int num=0, c=0, e=0;
			stringstream str(line);
				while(str >> num){
					c = num;
					str >> num;
					e = num;
					Node* temp = new Node(c,e);
					current->add(temp);
				}//while
		}//while
		myfile.close();		
	}//if
	else cout << "Unable to open file" << endl;
 
	cout << "\nSorted List: " << endl;
	current->display();
	cout << endl;
 
	LinkedList* add = new LinkedList;
	add = current;//how can I make add be a separate copy of current?
 
 
	add->operationAdd();
	add->display();
	current->display();
 
	return 0;
}

-1 0 5 1 20 3 -9 2 -2 1 1 2 -2 3 1 9 6 3 2 2 -1 1 10 0
5 2 -2 9 10 3 4 0 -3 1 1 1 6 3 -4 3 -5 2 8 8 9 4 4 4

	LinkedList(const LinkedList& l){
		Node* temp = l.start;
		if(temp == NULL){
			cout << "List is empty";
			exit(1);
		}//if
		else{
			while(temp != NULL){
				this->add(temp);
				temp = temp->next;
			}//while
 
		}//else
	}//copy constructor

2,2 -> 4,2 -> 6,2 -> 8,8