Linked List multiple nodes in C++ - c++

Question

Meet multiple problems while coding, I want to build a room reservation system with linked list,
I want the user can see the room number in the menu and when the room number is taken, the room number will be deleted from the menu.
Is there anyways to simplified the codes, my codes is very messy, please help thanks
1.First I used
struct nodes{
int single_room[5] = {101,102,103,104,105};
int double_room[4] = {201,202,203,204,205};
};
But when I want to compare the Linked List with user input it came out errors
void reservation::UpdateReservation(){
int x;
node *current;
current = head;
bool found;
found = false;
cout << "Please enter your room number to update your reservation:
";
cin >> x;
while ((current != NULL) && (!found))
{
if (current -> single_room == x)
found = true;
else
current = current -> link;
}
while(found)
{
cout <<"The number is exist";
cout << endl;
return found;
cout << value;
}
cout << "The number is not found";
cout << endl;
}
}
It came up an error with ISO C++ forbids comparison between pointer and integer.
After I put a for loop, for the single_room[i], but the current -> single_room[i] is empty..
I've stackoverflowed a lot of questions and found out I can't initialize a linked list, so I used one by one initialize value inside the notes
#include <iostream>
#include <fstream>
#include <windows.h>
#include <string>
using namespace std;
class reservation{
private:
struct node
{
int single_room;
int double_room;
int deluxe_suite;
int president_suite;
int room_number;
string name;
int phone_number;
int date;
int number_of_nights;
int number_of_pax;
int time;
node *link;
}*head;
public:
reservation();
void InitializeValue_single_room(int a);
void InitializeValue_double_room(int b);
void InitializeValue_deluxe_suite(int c);
void InitializeValue_president_suite(int d);
void menu();
void Room_size();
void InsertReservation();
void UpdateReservation();
// void DeleteReservation();
void DisplayReservation();
~reservation();
};
reservation::reservation()
{
head = NULL;
}
reservation::~reservation()
{
node *q;
if (head == NULL)
{
return;
}
while (head != NULL)
{
q = head->link;
delete head;
head = q;
}
}
void reservation::InitializeValue_single_room(int a)
{
node *newNode;
newNode = new node;
newNode -> single_room = a;
newNode -> link = head;
head = newNode;
}
void reservation::InitializeValue_double_room(int b)
{
node *newNode;
newNode = new node;
newNode -> double_room = b;
newNode -> link = head;
head = newNode;
}
void reservation::InitializeValue_deluxe_suite(int c)
{
node *newNode;
newNode = new node;
newNode -> deluxe_suite= c;
newNode -> link = head;
head = newNode;
}
void reservation::InitializeValue_president_suite(int d)
{
node *newNode;
newNode = new node;
newNode -> president_suite = d;
newNode -> link = head;
head = newNode;
}
void reservation::menu()
{
cout <<" 1. Book a reservation" << endl;
cout <<" 2. Update a reservation" << endl;
cout <<" 3. Delete a resevation" << endl;
cout <<" 4. Display the reservation" << endl;
cout <<" 5. Help" << endl;
cout <<" 6. Exit" << endl << endl;
cout << "Please enter here: ";
}
But I want to print out the value in the Room_size(), it would print out this
Sorry not enough reputation to upload an image, I just describe here, it would came out|01704272||1704272||1704272||1704272||
1704272||1704272||1704272||1704272||1728736||101||102||103||104||105|
It would print out the numbers which I don't want, I only want 101,102,103,104,105 to view
void reservation::Room_size()
{
node guest;
node *current, *current1;
current = head;
current1 = head;
cout << " Single Room: " << endl;
cout << " ";
while (current != NULL)
{
cout << current -> single_room;
current = current -> link;
if(current != NULL)
cout << "|" << "|";
}
cout << "|" << endl;
cout << " Double Room: " << endl;
cout << " ";
while (current1 != NULL)
{
cout << current1 -> double_room;
current1 = current1 -> link;
if(current1 != NULL)
cout << "|" << "|";
}
cout << "|" << endl;
}
void reservation::InsertReservation()
{
node guest;
node *current;
current = head;
bool found;
found = false;
char b;
int c;
bool d = true;
bool f = false;
do{
ofstream file;
file.open("Guest info.txt", ios::out|ios::app);
if(!file)
{
cout << "ERROR: File can't open";
system("pause");
}
cout<<"Please enter your Name: ";
getline(cin,guest.name);
cout << endl;
while(!f){
cout << "Please enter your phone number: +";
cin >> guest.phone_number;
if(guest.phone_number < 10)//|| (cin >> guest.phone_number) < 11)
{
cout << "Wrong input! ";
f = false;
}
else{
f = true;
cin.ignore();
}
cout << endl;
}
cout << "Please enter the date you want to book: (20/04): ";
cin >> guest.date;
cout << endl;
cout << "Please enter the number of nights you want to stay: ";
cin >> guest.number_of_nights ;
cout << endl;
cout << "Please enter the time you want to check in (24:00 format): ";
cin >> guest.time;
cout << endl;
cout << "Please enter the number of people you have: ";
cin >> guest.number_of_pax;
while(d){
cout << "1.Single Room\n2.Double Room \n3.Luxury Suite \n4.President Suite\n\n";
cout << "Please select the room you want: ";
cin >> c;
if(c==1)
{
cout << " Rooms that are available: " << endl;
cout << " Single rooms: " << endl;
cout << " |" << guest.single_room << "|";
cout << endl << endl;
cout << "Please enter the room number you want to book: ";
cin >> guest.room_number;
d = false;
}else if(c==2)
{
cout << " Rooms that are available: " << endl;
cout << " Double rooms: " << endl;
cout << " |" << guest.double_room << "|";
cout << endl << endl;
cout << "Please enter the room number you want to book: ";
cin >> guest.room_number;
d = false;
}else if(c==3)
{
cout << " Rooms that are available: " << endl;
cout << " Luxury Suite: " << endl;
cout << " |" << guest.deluxe_suite << "|";
cout << endl << endl;
cout << "Please enter the room number you want to book: ";
cin >> guest.room_number;
d = false;
}else if (c==4)
{
cout << " Rooms that are available: " << endl;
cout << " President Suite" << endl;
cout << " |" << guest.president_suite << "|";
cout << endl << endl;
cout << "Please enter the room number you want to book: ";
cin >> guest.room_number;
d = false;
}else
{
cout << "Wrong input. Please try again";
d = true;
}
}
int e;
cout << "Press 1 to Save or 2 to cancel:";
cout << endl;
cin >> e;
if(e==1)
{
cout << endl;
file << "Guests info" << endl;
cout << endl;
file << "=================================================="<< endl;
file << endl;
file << "Room Number: " << guest.room_number;
file << endl;
file << "Name: " << guest.name << endl;
file << endl;
file << "Phone Number: " << guest.phone_number << endl;
file << endl;
file << "Date: " << guest.date << endl;
file << endl;
file << "Number of nights: " << guest.number_of_nights << endl;
file << endl;
file << "Time: " << guest.time << endl;
file << endl;
file << "Number of pax: " << guest.number_of_pax << endl;
file << endl;
file << endl;
file << "====================================================" << endl;
file.close();
cout << "Record Saved " << endl;
cout << "======================================================" << endl;
}else
{
cout << "Record was not saved " << endl;
cout << "====================================================" << endl;
cout << endl;
}
/* while ((current != NULL) && (!found))
{
if (current -> single_room == (guest.room_number))
found = true;
else
current = current -> link;
while(found)
{
cout << "ROOM NUMBER FOUND";
cout << endl;
}
cout << "NO";
cout << endl;
}*/
cout << "Enter (Y/y) to input another data or enter (N/n) to Exit";
cin >> b;
cout << "======================================================" <<
endl;
cout << endl;
}while(b == 'y' || b == 'Y');
if(b =='y'|| b=='Y')
{
cin.ignore();
}
}
void reservation::DisplayReservation()
{
node *current;
current = head;
cout << " |";
while (current != NULL)//) && current-> deluxe_suite <400))
{
cout << current -> deluxe_suite;
current = current -> link;
if(current != NULL)
cout << "| "<< "|";
}
cout << "|" << endl;
}
int main()
{
reservation r;
r.InitializeValue_single_room(105);
r.InitializeValue_single_room(104);
r.InitializeValue_single_room(103);
r.InitializeValue_single_room(102);
r.InitializeValue_single_room(101);
r.InitializeValue_double_room(204);
r.InitializeValue_double_room(203);
r.InitializeValue_double_room(202);
r.InitializeValue_double_room(201);
r.InitializeValue_deluxe_suite(303);
r.InitializeValue_deluxe_suite(302);
r.InitializeValue_deluxe_suite(301);
r.InitializeValue_president_suite(888);
r.InitializeValue_president_suite(666);
cout <<"================================================" << endl << endl;
cout <<" Welcome to the Hotel Reservation Application" << endl << endl;
cout <<"================================================" << endl;
int a;
cout << "Please wait while the system is analyzing hte data\n";
cout << endl;
cout<<"===================================" << endl;
cout <<" Main Menu " << endl << endl;
cout << " Rooms that are available: " << endl;
r.Room_size();
cout << endl << endl;
cout << "===================================" << endl;
r.menu();
cin >> a;
if(a == 1)
{
system("CLS");
cout << "===================================" << endl;
cout << " BOOK A RESERVATION" << endl;
cout << "===================================" << endl;
cin.ignore();
r.InsertReservation();
}else if(a == 2)
{
system("CLS");
cout << "===================================" << endl;
cout << " UPDATE YOUR RESERVATION" << endl;
cout << "===================================" << endl;
cin.ignore();
// r.UpdateReservation();
}else if(a == 4)
{
system("CLS");
cout <<"===================================" << endl;
cout << " VIEW ALL RESERVATION" << endl;
cout << "===================================" << endl;
cin.ignore();
r.DisplayReservation();
}
return 0;
}

Answer 1

I just ran your code.
What is happening is that you have single rooms, double, delux and president suite rooms in the same class, with the same list. It's not the best way to go, but it is a way to go.
This is the result that I got
Rooms that are available:
Single Room:
0||0||0||0||0||0||0||0||0||101||102||103||104||105|
Double Room:
0||0||0||0||0||201||202||203||204||0||0||-805306368||-805306368||-805306368|
You initialised the list as
r.InitializeValue_single_room(105);
r.InitializeValue_single_room(104);
r.InitializeValue_single_room(103);
r.InitializeValue_single_room(102);
r.InitializeValue_single_room(101);
r.InitializeValue_double_room(204);
r.InitializeValue_double_room(203);
r.InitializeValue_double_room(202);
r.InitializeValue_double_room(201);
r.InitializeValue_deluxe_suite(303);
r.InitializeValue_deluxe_suite(302);
r.InitializeValue_deluxe_suite(301);
r.InitializeValue_president_suite(888);
r.InitializeValue_president_suite(666);
Since the list is last in first out type, when you iterate through the list in the Room_size() function your function sees the following in the list
The first 2 rooms are president suites, where only president_suite attribute is set
The next 3 rooms are delux, where only deluxe_suite attribute is set
the next 4 rooms are double, where only double_room attribute is set
and the last 5 rooms are, where only single room attribute is set
So when it is printing single rooms, the first 9 nodes do not have the single room attribute set, as such it prints some garbage value, 5 times and then prints the correct single room number, and
Similarly for double room, it prints 5 garbage values and then prints the right numbers, and then 5 more garbage values.
to correct this problem you need to make the following changes.
1) In the class definition, use a single variable for room number, and another variable for room type.
2) Set room type constants using enum
enum room_types={single,double,delux,president_suite}
3) When a room is initialised via the InitializeValue_**, the function should set the room number from the arguments to the room number in the node, but should set room type attribute as per the enum. for example in the InitializeValue_single_room function
void reservation::InitializeValue_single_room(int a)
{
node *newNode;
newNode = new node;
newNode -> room_number = a;
newNode -> room_type = single;
newNode -> link = head;
head = newNode;
}
4) When you call the room_size() function, while printing the room types check for the room type. Example :
cout << " Single Room: " << endl;
cout << " ";
while (current != NULL)
{
if(current -> room_type !=single){
current = current -> link;
continue;
}
cout << current -> room_number;
current = current -> link;
if(current != NULL)
cout << "|" << "|";
}
I hope this helps.
There are much better ways to implement this, but I believe this is the best way for you for now.