Help, I totally don't understand why my code is not working

[WanHazyan]

Honestly, I'm new to C++ and don't really understand the structure yet. My professor give me a homework to do which is what I am trying to do right now. The program that my company should run is a virtual architecture design business and my company is specialize in designing specific types of room . I need a system to keep record on all the orders made by customers systematically.

This one is the header file

  #include <iostream>
#include <string>

#include <conio.h>
using namespace std;
string roomType;
int roomNumber;
int bed;
int table;
int towel;
int sofa;



class Node
{
public:

	string roomType;
	int roomNumber;
	int bed;
	int table;
	int towel;
	int sofa;
	Node *next;

	Node(int x, string a, int b, int c, int d, int e, Node *z)
	{
		roomType = a;
		roomNumber = x;
		bed = b;
		table = c;
		towel = d;
		sofa = e;
		next = z;
	}
};



class Room
{
private:
	Node *head;
	int count;
public:
	Room();//Room(DoubleRoom);
	void Menu();
	void roomtype(int);
	void addRoom();
	void deleteRoom(int x);
	void viewRoom();

};

class Roomtype : Room
{
private:
	Node * head;
public:
	Roomtype();
	string single();
	string twin();
	string supreme();

};

and this is the cpp file

#include<iostream>
#include<string>
#include<cstdlib>
#include<ctime>
#include<iomanip>
#include"room.h"
using namespace std;
//---------------------------------------------== CLASS CUSTOMER ==---------------------------------------------------------------------------
class customer
{

public:

	int id;
	string name;
	customer*next;
	int phone;


	customer(int x, string y, customer *z, int b) //Constructor witn parameter
	{
		id = x;
		name = y;
		next = z;
		phone = b;

	}
};



//--------------------------------------------==CLASS ROOMREGISTRATION==-----------------------------------------------------------------

class RoomRegistration
{
private:customer*head;

		double total1;
		double total2;

public:
	RoomRegistration()
	{
		head = 0;
		total1 = 0.00;
		total2 = 0.00;
	}

};
//----------------------------------------------==MENU==------------------------------------------------------------------------------------
	void menu()
	{
		cout << " 1.Add customer\n 2.Delete a customer\n 3.Edit customer\n 4.View customer\n 5.Total customer and order\n 6.Exit\n";
		cout << " \n\n Please enter your choice: ";
	}

//-----------------------------------------------== ADD FUNCTION ==--------------------------------------------------------------------------
void addcust()

	{
		customer*p;
		p = head;
		int id = 0;

		string name = " ";
		string strg;
		int phone;


		cout << " Enter Your Name = ";
		cin >> name;
		cout << " Enter Your Id  = ";
		cin >> id;
		customer *temp, *second, *third;
		temp = head;
		while (temp != NULL)
		{
			if (temp->id == id)
			{
				cout << " Cannot add repeated id\n\n" << endl;
				system("pause");
				return;
			}
			temp = temp->next;
		}

		cout << " Enter Your Phone Number = ";
		cin >> phone;


		system("pause");
		system("cls");


		if (head == NULL)
		{
			head = new customer(id, name, NULL, phone);
		}

		else if (head->id > id)
		{
			second = head;
			head = new customer(id, name, NULL, phone);
			head->next = second;

		}

		else if (head->id > id)
		{
			second = head;
			third = head;

			while (second != NULL && second->id < id)
			{
				third = second;
				second = second->next;
			}

			p = new customer(id, name, NULL, phone);
			p->next = second;
			third->next = p;
		}
	}
	void Room::addRoom()
	{
			cout << "Please enter your information: " << endl;
			cout << " Room type" << endl;
			cout << "\n1.single\n2.double\n3.supreme\n:";
			cin >> roomType;
			cout << "Room Number ";
			cin >> roomNumber;
			cout << "No of bed: ";
			cin >> bed;
			cout << "No. of Table: ";
			cin >> table;
			cout << "No. of Towel: ";
			cin >> towel;
			cout << "No. of Sofa: ";
			cin >> sofa;
			cout << "Room Registered." << endl;

			Node *p;
			if (head == NULL)
			{
				head = new Node(roomNumber, roomType, bed, table, towel, sofa, NULL);
			}
			else
			{
				p = head;
				while (p->next != NULL)
					p = p->next;
				p->next = new Node(roomNumber, roomType, bed, table, towel, sofa, NULL);
			}

			//count ++;
	
}

//-----------------------------------------------==DROP FUNCTION ==--------------------------------------------------------------------------
void drop()
{
	int id;
	cout << " Enter id: ";
	cin >> id;
	customer *del = NULL;
	customer *temp = head;
	customer *second = head;

	while (second != NULL && ((*second).id) != id)
	{
		temp = second;//let temp point to watever end is pointed to
		second = (*second).next;
	}

	if (second == NULL)
	{
		cout << id << " No Data Deleted" << endl;
		delete del;//free memory;
	}

	else
	{
		del = second;
		second = (*second).next;
		(*temp).next = second;

		if (del == head)
		{
			head = (*head).next;
			temp = NULL;
		}

		delete del;
		cout << "The value " << id << " was deleted." << endl;
	}

}

[coder777]

What exactly doesn't work?

class Roomtype : Room // Note: this private inheritance, i.e. Roomtype cannot access anything from Room
{
private:
	Node * head; // Note: This shadows head from Room, i.e. head exists twice
public:
	Roomtype();
	string single();
	string twin();
	string supreme();

};

void addcust()

	{
		customer*p;
		p = head; // Where does this head come from? 

You cannot/shall not define variables in a header file. You will get multiple definition error by the linker if the header is included more than once.

[WanHazyan]

Ouh, I see..

actually I'm upgrading the code from my previous assignment
So...I don't really understand how to do the improvement
The previous code work just fine, but when I add things, it produce multiple errors