I need help with this code. this is part of a code that makes a list of books. I had the question parts of the code because im confused on how to do this. $//$ Q$3$b: Define Friend Function changeLibraryType$()(3$ points$)$

$//$ Define the function changeLibraryType$()$that is declared in room.h file.

$//$ This function sets the new library type for the room. The room object and new library type $($as integer$)$ are to be passed as function arguments.

$//$ Use $\text{'}$d$\text{'}$ display option after using $\text{'}$c$\text{'}$ option to verify.

$//$ You will need to implement add$()$ and displayList$()$ before you test this function.

void changeLibraryType$($Room$*$ room,int no$\_$input$)$

$\{$

room$->$Type $=$ no$\_$input;

$\}$

$//$ Q$4$: addRoom $(7$ points$)$

$//$ This function is used to add a new room to the global linked list 'list'. You may add the new room to head or tail of the list. $($Sample solution adds to tail$)$

$//$ libraryType 'type' can be hayden or noble. You will need to use the function argument $$type$$ to determine which constructor to use to create new room node.

$//$ For example, if the user enters type as 'noble', then you need to use Noble class and constructor to create new room node and add it to the list.

$//$ NOTE: In executeAction$(),$ searchroom$()$ is called before this function. Therefore no need to check here if the room exists in the list.

$//$ See how this fucntion is called in case $\text{'}$a$\text{'}$ of executeAction$()$

void addRoom$($string name$\_$input, int no$\_$input, libraryType type$)$

$\{$

Container$*$ tempList $=$ list; $//$ work on a copy of 'list'

Container$*$ newContainer $=$ new Container$()$;

Room$*$ newroom;

if$($type $==0)\{$

newroom $=$ new Hayden$($name$\_$input, no$\_$input, type$)$;

$\}$else$\{$

newroom $=$ new Noble$($name$\_$input, no$\_$input, type$)$;

$\}$

newContainer$->$room $=$ newroom;

newContainer$->$next $=$ NULL;

if $($list $==$ NULL$)$

list $=$ newContainer;

else$\{$ while$($tempList$->$next $!=$ NULL$)\{$

tempList $=$ tempList$->$next;

$\}$

tempList$->$next $=$ newContainer;

$\}$

$\}$

$//$ Q$5$: displayList $(4$ points$)$

$//$ This function displays the list of room and their details $($name$,$ no$,$ library name$)$

$//$ Parse the list and use the class member function to display the room info.

$//$ See expected output in the question file.

void displayList$()$

$\{$

Container $*$tempList $=$ list; $//$ work on a copy of 'list'

$//$this should check if the list is null or display list if not null

if$($list $==$ NULL$)$

cout $<<$ "list is empty" $<<$ endl;

while$($tempList $!=$ NULL$)\{$

tempList$->$room$->$displayRoom$()$;

tempList $=$ tempList$->$next;

$\}$

$\}$

$//$ Q$6$: save $(7$ points$)$

$//$ Save the linked list of rooms to a file list.txt using ofstream.

$//$ You will need to save the number of rooms in linked list. That will help in load$()$ when reading the file.

$//$ One format to store is:

$//$

$//$

$//$

$//$

$//$

$//$

$//$

$//$ and so on$..$

$//$ You may store the list in another format if you wish. You need to read the file in load $()$ the same way that it is saved in save$().$

$//$ This function is called when exiting the program $($end of main$()).$

$//$ Hint: You may want to cast the enum $$libraryType$$ to an int before writing it to the file.

void save$($string fileName$)$

$\{$

$\}$

$//$ Q$7$: load $(7$ points$)$

$//$ Load the linked list of rooms from the file using ifstream.

$//$ You will need to create the linked list in the same order that is was saved to the file in save$().$

$//$ First, read the number of rooms saved in the file.

$//$ Then, for every room you will need to create a new Room node depending on room type. You may add the room to head or tail of the list.

$//$ Hint: If you casted the enum 'libraryType' to an int, you will need to cast it back to 'libraryType' when making the room node.

$//$ This function is called at the beginning of main$().$

void load$($string fileName$)$

$\{$

$\}$