Insertion element at middle of the SLL (or) Insertion element at ith node

//Insertion element at middle of the SLL (or)  Insertion element at ith node
#include<iostream.h>
#include<conio.h>
#include<stdio.h>
template<class T>
class sll;
template<class T>
class node
{
 private:
  T data;
  node<T>* link;
 friend class sll<T>;
};
template <class T>
class sll
{
 private:
  node<T> * first;
 public:
 //Mem.Fun declarations
  sll();
   int isempty();
  void display();
  int length();
   void append(node<T> *k);
  void create();
  void insert(int i, T x);
};
//Member Functions defination
template<class T>
sll<T>::sll()
{
 first=NULL;//first points to no where,it is an empty node
}
template<class T>
int sll<T>::isempty()
{
 return(first==NULL);//return true when linked list is empty and false otherwise
}
template<class T>
void sll<T>::display()
{
 node<T>* p;//p is pointer to a node
 if(isempty())
  cout<<"Linked List is empty\n";
 else
 {
  cout<<"Linked list is as follows\n";
  p=first;
  while(p!=NULL)
  {
   cout<<p->data<<"\t"<<p->link<<"\n";
   p=p->link;
  }
 }//end of else
}//end of display()
template<class T>
void sll<T>::append(node<T> *k)
{
 node<T> *last;
 k->link=NULL;
 if(isempty())
  first=k;
 else
 {
  last=first;
  while(last->link!=NULL)//keep moving last pointer until last node is reached
  {
   last=last->link;
  }
  last->link=k;//attach last node and new node k
 }
}
template <class T>
void sll<T>::create()
{
 T x;
 node<T> *k;
 first=NULL;
 cout<<"enter values terminated by -1 or !\n";
 cin>>x;
 while(x!=-1&&x!='!')
 {
  k=new node<T>;
  k->data=x;
  append(k);
  cin>>x;
 }
}//end of create()
 //inserting  data at ith node
template<class T>
void sll<T>::insert(int i, T x)
{
   node<T> *p,*temp;
  if(i<0||i>length())
  {
    cout<<"Non-Existing Node\n";
   }
  else
  {
    p=new node<T>;
   //store data into the node
   p->data=x;
   if(i= =0) //insert at the begining or Linked list is empty
  {
    p->link=NULL;
   first=p;
  }
  else //insert in the middle or at the end of the Linked List
  {
    temp=first;
    //move the temp ptr to ith node (desired node)
   for(int j=1;j<=i-1;j++)
     temp=temp->link;
  //insert new node p after temp node
  p->link=temp->link;
 temp->link=p;
 } //inner else
}//outer else
 }//end of insert()
   

void main()
{
 sll<int> a;//creating object a, d.c is called
 clrscr();
  int i,x;
 a.create();
 cout<<"enter which position you want to insert(ith node value)\n";
  cin>>i;
  cout<<"enter data to be inserted\n";
  cin>>x;
  a.insert(i,x);
 a.display();
  getch();
}
output:


Singly Linked List Operations




Types of Linked list

Single Linked List

 Dobule Linked List
Circular Linked List