// WAP to dlete an element from a Linked List

#include <iostream.h>
#include <conio.h>
#include <stdio.h>


struct del
{
   int element;

   del *next;
};

void main()
{
   del *first, *last, *x , *back;
   int i,n;
   cout << "Enter the size of the list ";
   cin >> n;
   if( n <= 0 )
     cout << "Invalid size entered";

   //CREATION OF LINKED LIST
   first = new del;
   cout << "Enter data of first node: \n";
   cin >> first->element ;
   first->next = NULL;
   last = first;
   for(i=0; i<(n - 1); i++)
   {
      x = new del;
      cout << "Enter data of Node " << (i+2) << " \n";
      cin >> x->element ;
      x->next = NULL;
      last->next = x;
      last = x;
   }

   del *temp;
   temp = new del;

   int ch;
   cout << "\n\t\tThe element should be deleted: ";
   cout << "\n\t\t\t1. First Element ";
   cout << "\n\t\t\t2. In the Middle";
   cout << "\n\t\t\t3. Last Element";
   cout << "\n\t\t\tEnter your choice: ";
   cin >> ch;

   if(ch == 1)
   {

      temp = first->next;
      first->next  = NULL;
      first = temp;

      // TRAVERSAL OF LINKED LIST
      temp = first;
      cout << "The entered list is: \n";
      while(temp != NULL)
      {
         cout << temp->element <<"\n" ;
         temp = temp->next ;
      }
      getch();

   }

   if (ch == 2)
   {
      int value;
      cout << "Enter the value of the node to be deleted: \n";
      cin >> value;
      temp = first;
      back = temp;
      temp = temp->next;
      while(temp != NULL)
      {
         if(temp->element == value)
         {
            back->next = temp->next;
            delete temp;
         }
         else
         {
            back = temp;
            temp = temp->next;
         }
      }

      // TRAVERSAL OF LINKED LIST
      temp = first;
      cout << "\nThe entered list is: \n";
      while(temp != NULL)
      {
         cout << temp->element << "\n" ;
         temp = temp->next ;
      }
      getch();
   }


   if(ch == 3)
   {
      back = first;
      temp = first->next;
      while(temp->next != NULL)
      {
          back = temp;
          temp = temp->next;
      }
      back->next = NULL;
      delete last;

      // TRAVERSAL OF LINKED LIST
      temp = first;
      cout << "The entered list is: \n";
      while(temp != NULL)
      {
         cout << temp->element << "\n" ;
         temp = temp->next ;
      }

      getch();
   }
}