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

struct Node
{
  int data;
  Node *next;
};
Node *start=NULL;
void menu()
{
  cout<<"\n1. Add Element At Last";
  cout<<"\n2. Add Element At First";
  cout<<"\n3. Delete Element By Value";
  cout<<"\n4. Display List";
  cout<<"\n5. Insert Element By Location";
  cout<<"\n9. Exit";

}
  Node * createNode()
    {
      Node *t=new Node;
      cout<<"\nEnter value for new node";
      cin>>t->data;
      t->next=NULL;
      return(t);
    }
void addElementLast()
{
     Node *temp= createNode();
     if(start==NULL)
     {
       start=temp;
     }
     else
     {
	Node *t=start;
	while(t->next!=NULL)
	{
	  t=t->next;
	}
	t->next=temp;

     }
}
void addElementFirst()
{
  Node *temp=createNode();
  temp->next=start;
  start=temp;
}
void displayList()
{
   Node *t=start;
   cout<<"\n";
   while(t!=NULL)
   {
     cout<<t->data<<"   ";
     t=t->next;
   }
}
void insertElementByLocation()
{
  int l;
  cout<<"\nenter location";
  cin>>l;
   Node *t=createNode();
   Node *t1,*t2;
   t1=start;
   t2=start->next;
   for(int i=1;i<=l-2;i++)
   {
     t1=t1->next;
     t2=t2->next;
   }

      t1->next=t;
      t->next=t2;



}
void deleteElementByValue()
{
  int n;
  cout<<"\nEnter value to be delete";
  cin>>n;
  if(start->data==n)
  {
    start=start->next;
  }
  else
  {
     Node *t=start;
     int flag=0;
     while(t->next->data!=n)
     {
       if(t->next==NULL)
       {
	 cout<<"\nNot Found";
	 flag=1;
	 break;
       }
       t=t->next;
     }
     if(flag==0)
     t->next=t->next->next;
  }
}
void main()
{

  int ch;
  clrscr();

  while(1)
  {
     menu();
     cout<<"\nEnter your choice";
     cin>>ch;
     switch(ch)
     {
       case 1:
	      addElementLast();
	      break;
       case 2:
	       addElementFirst();
	       break;
       case 3:
		 deleteElementByValue();
		 break;
       case 4:
	       displayList();
	       break;
       case 5:
	       insertElementByLocation();
	       break;
       case 9:
	      exit(0);
     }
  }

  getch();
}