#include <iostream.h>
#include <ctype.h>
#include <string.h>
 
#define MAX_NAME_LEN 30
 
 
typedef struct Sheet
{
 char Name[MAX_NAME_LEN + 1];
 struct Sheet *Next, *Prev;
}Sheet;
 
 
 
//prototypes
void initialise(Sheet *&, char arr[], Sheet *&);
void right(Sheet *);
void left(Sheet *);
void first(Sheet *&);
void last(Sheet *&);
void erase(Sheet *);
void insert(char word[], Sheet *&, Sheet *&);
void rename();
void display(Sheet *&);
void strToLower(char s[]);
 
 
 
 
 
void main()
{
 
	Sheet *Head = NULL, *Tail = NULL;
	Sheet *mvlr=NULL;
 
 char init1[MAX_NAME_LEN+1]="sheet1";
	char init2[MAX_NAME_LEN+1]="sheet2";
	char init3[MAX_NAME_LEN+1]="sheet3";
 
 
 initialise(Head, init1, Tail);
	initialise(Head, init2, Tail);
	initialise(Head, init3, Tail);
 
	char Option; 
 char OldName[MAX_NAME_LEN+1], NewName[MAX_NAME_LEN+1];
 
 
 cout<<"************ Selection Options *************"<<endl;
 cout<<endl;
 
 while(Option != 'E')
 {
 cout<<"Press 'R' to move to the next sheet\n";
 cout<<"Press 'L' to move to the previous sheet\n";
 cout<<"Press 'H' to jump to the first sheet\n";
 cout<<"Press 'T' to jump to the last sheet\n";
 cout<<"Press 'S' to add a new sheet to the list\n";
 cout<<"Press 'D' to delete a sheet from the list\n";
 cout<<"Press 'V' to view the sheets currently in the list\n";
 cout<<"Press 'N' to rename a sheet\n";
 cout<<"Press 'E' to exit\n";
 cout<<endl;
 
 cout<<"Enter your option: ";
 cin>>Option;
 Option = toupper(Option); 
 
 switch(Option)
 {
 case 'R':
  right(Head);
	 break;
 
 case 'L':
  left(Head);
  break;
 
 case 'H':
  first(Head);
  break;
 
 case 'T':
  last(Tail);
  break;
 
 case 'S':
  cout<<"Enter a name for this new sheet: ";
  cin>>NewName;
  strToLower(NewName);
  insert(NewName, Head, Tail);
  cout<<endl;
  break;
 
 case 'D':
  cout<<"Enter the name of the sheet you wish to delete: "; 
		cin>>OldName;
  strToLower(OldName);
  erase(Head);
  break;
 
 case 'V':
  cout<<"Displaying list: "<<endl;
  display(Head);
  cout<<endl;
  break;
 
 case 'N':
  cout<<"Enter name to change: ";
		cin>>OldName[MAX_NAME_LEN + 1];
  strToLower(OldName);
  cout<<"Enter new name for sheet: ";
		cin>>NewName[MAX_NAME_LEN + 1];
  strToLower(NewName);
  rename();
  break;
 
 case 'E':
  break;
 
 default:
  cout<<endl;
  cout<<"Please select an option from the list"<<endl;
  cout<<endl;
  break;
 
	 }//end switch
 }//end while 
 
 
}//end main
 
void initialise(Sheet *&L, char arr[], Sheet *&T) 
{
	Sheet *e, *curr, *prev;
 
	e = new Sheet;
	strcpy(e->Name, arr);
	e->Next = NULL;
	e->Prev = NULL;
 
	if(L == NULL)
 {
		L = e;
	}
 else
 {
	prev = curr = L;
 
 while(curr != NULL)
 {
	   prev = curr;
	   curr = curr->Next;
	}
		e->Next = NULL;
		prev->Next = e;
		e->Prev = prev;
		T = e;
	}
 
}
 
 
void right(Sheet *Head)
{
 Sheet *Current, *Previous;
 
 Current = Head;
 Current = Current->Next;
 Previous = Current->Prev;
 
 cout<<"Current Sheet: "<<Current->Name;
 cout<<endl;
}
 
void left(Sheet *mvlr)
{
 Sheet *Current = new Sheet, *Previous = new Sheet;
 
 cout<<"Previous Sheet: "<<Current->Name<<endl;
 Current = Current->Prev;
 Previous = Current->Next;
 cout<<"Current Sheet: "<<Current->Name<<endl;
 
 
 if(Current->Prev == NULL)
 {
  cout<<"No more sheets!!!11!one"<<endl;
 }
 cout<<endl;
}
 
 
void first(Sheet *&L)
{
	Sheet *e;
	e = L;
	cout<<"The first sheet in the list is:"<<'\t';
 cout<<e->Name<<endl;
 cout<<endl;
}
 
void last(Sheet *&L)
{
	Sheet *e;
	e = L;
	cout<<"The last sheet in the list is: "<<'\t';
	cout<<e->Name<<endl;
 cout<<endl;
}
 
 
void erase(Sheet *L)
{
 Sheet *Current = L;
 
 while(Current != NULL || (!strcmp("OldName", Current->Name)))
 {
  Current = Current->Next;
  delete Current;
  L = Current;
 }
}
 
 
//function to insert a new sheet
//inserts at end of list only.
void insert(char word[], Sheet *&L, Sheet *&T)
{
	Sheet *e, *curr, *prev;
 
		e = new Sheet;
		strcpy(e->Name, word);
		e->Next = NULL;
		e->Prev = NULL;
 
		if(L == NULL)
  {
			L = e;
		}
  else
  {
		prev = curr = L;
 
  while(curr != NULL)
  {
		   prev=curr;
		   curr=curr->Next;
		}
		   e->Next = NULL;
		   prev->Next = e;
		   e->Prev = prev;
		   T = e;
	}
}
 
 
//function to display the current sheets in list
void display(Sheet *&L)
{
	Sheet *****;
	**** = L;
 
	while(**** != NULL)
 {
		cout<<****->Name<<endl;
		**** = ****->Next;
	}
}
 
 
//function to rename a sheet
void rename()
{
 Sheet *Current;
 char OldName[MAX_NAME_LEN + 1], NewName[MAX_NAME_LEN + 1];
 
 if(!strcmp(Current->Name, OldName))
 {
  strcpy(NewName, Current->Name);
  cout<<Current->Name;
 }
}
 
 
void strToLower(char s[])
{ int i ;
 for(i=0 ; s[i] != '\0' ; i++) 
 {
  s[i] = tolower(s[i]) ;
 }
}

// "DoublyLinkedList.cpp"
#include<iostream>
#include<conio.h>
using namespace std;
class node
{ 
public:
 int data;
 node *right_link, *left_link;
};
class friend_node
{
private:
 
 node *head, *current_node;
 void add_to_list(int);
 int move_right();
 int move_left();
 void display_list();
 void delete_record();
 void dispose_list();
 void print_options();
public:
 
 friend_node();
 ~friend_node();
 void handle_choice();
};
friend_node::friend_node()
{
 head = new node;
 head->data = 0;
 head->left_link = head;
 head->right_link = head;
 current_node = head;
}
friend_node::~friend_node()
{
 delete head;
}
void main()
{
 friend_node go;
 cout << "Welcome to the Doubly Linked List Simulation\n\n";
 cout << "1 - Exit program\n";
 cout << "2 - Add\n";
 cout << "3 - Move left\n";
 cout << "4 - Move right\n";
 cout << "5 - Print\n";
 cout << "6 - Delete\n";
 cout << "7 - Dispose\n";
 cout << "8 - Show these options again\n";
 go.handle_choice();
}
void friend_node::handle_choice()
{
 friend_node free_memory;
 int value;
 int choice;
 while (choice != 1)
 {
  cout << "\nEnter choice: ";
  cin >> choice;
  int temp = 0;
  switch(choice)
  {
   case 1:
   free_memory.~friend_node();
   cout << "\nThank you!\n\n";
   getch();
   exit(1);
   break;	  
 
   case 2:
   cout << "\nEnter a number: ";
   cin >> value;
   temp = value;
   cout << "\n" << temp << " has been added!\n";
   getch();
   add_to_list(value); 
   break;	  
 
   case 3:
   cout << "\nCurrent data to the left is:  " << move_left() << "\n\n";
   getch();
   break;	  
 
   case 4:
   cout << "\nCurrent data to the right is:  " << move_right() << "\n\n";
   getch();
   break;
   case 5:
   display_list();
   break;
 
   case 6:
   delete_record();
   break;
   case 7:
   dispose_list();
   break;
 
   case 8:
   print_options();
   break;
   default:
   cout << "\nInvalid choice!\n\n";
   getch();
   break;
  }
 }
}
void friend_node::add_to_list(int add_data)
{
 node *add = new node;
 add->data = add_data;
 add->left_link = current_node;
 add->right_link = current_node->right_link;
 current_node->right_link->left_link = add;
 current_node->right_link = add;
 current_node = add;
}
int friend_node::move_left()
{
 char empty[30] = {"\n\n\a\a\a\aThe list is empty!\n\n"};
 if(head->right_link == head)
 {
  cout << empty << endl;
  getch();
  handle_choice();
 }
 else
 {
  current_node = current_node->left_link;
 
  if(current_node == head)
  {
   current_node = current_node->left_link;
   return (current_node->data);
  }
  else
   return(current_node->data);
 }
 return (0);
}
int friend_node::move_right()
{
 char empty[30] = {"\n\n\a\a\a\aThe list is empty!\n\n"};
 
 if(head->right_link == head)
 {
  cout << empty << endl;
  getch();
  handle_choice();
 }
 
 else
 {
  current_node = current_node->right_link;
  if(current_node == head)
  {
	current_node = current_node->right_link;
	return (current_node->data);
  }
  else
   return(current_node->data);
 }
 return (0);
}
void friend_node::display_list(void)
{
 char empty[30] = {"\n\n\a\a\a\aNothing to print!\n\n"};
 node *print;
 if(head->right_link == head)
 {
  cout << empty << endl;
  getch();
  handle_choice();
 }
 else
 {
  cout << "\nCurrent data in the list:  ";
  print = head->right_link;
  while(print != head)
  {
   cout << print->data <<" ";
   print = print->right_link;
  }
 }
 getch();
 cout <<"\n\n";
}
void friend_node::delete_record()
{
 char empty[30] = {"\n\n\a\a\a\aNothing to delete!\n\n"};
 node *temp_current = new node;
 node *temp_current2 = temp_current;
 temp_current = current_node;
 if (head->right_link == head)
 {
  cout << empty << endl;
  getch();
  handle_choice();
 }
 while(current_node != head)
 {
  cout << "\n\n" << current_node->data << " has been deleted!\n\n";
  current_node->left_link->right_link = current_node->right_link;
  current_node->right_link->left_link = current_node->left_link;
  current_node = current_node->right_link;
  current_node = current_node->left_link;
  getch();
  handle_choice();
 }
}
void friend_node::dispose_list()
{
 char empty[30] = {"\n\n\a\a\a\aNothing to dispose!\n\n"};
 if(head->right_link == head)
 {
  cout << empty << endl;
  getch();
  handle_choice();
 }
 while(current_node != head)
 {
  current_node->left_link->right_link = current_node->right_link;
  current_node->right_link->left_link = current_node->left_link;
  current_node = current_node->right_link;
  current_node = current_node->left_link;
  if(current_node == head)
  {
   cout << "\n\nThe list has been disposed!\n\n";
   getch();
  }
 }
}
void friend_node::print_options()
{
 cout << "\n\n1 - Exit program\n";
 cout << "2 - Add\n";
 cout << "3 - Move left\n";
 cout << "4 - Move right\n";
 cout << "5 - Print\n";
 cout << "6 - Delete\n";
 cout << "7 - Dispose\n";
 cout << "8 - Show these options again\n\n";
}