lab 20/03/17 2 way linked list insertion

#include<bits/stdc++.h>

using namespace std;

class node
{
public:
    int info;
    node *forw,*backw;
};
node *first=NULL,*last,*temp;
void creat_list(int data)
{
    node *srt;
    srt=new node();
    srt->info=data;
    srt->forw=NULL;
    srt->backw=NULL;
    if(first==NULL)
    {
        first=srt;
        temp=srt;
        temp->backw=NULL;
    }
    else
    {
        temp->forw=srt;
        srt->backw=temp;
        srt->forw=NULL;
        temp=srt;
    }
    last=srt;
}
void insert_1st(int data)
{
    node *srt;
    srt=new node();
    srt->info=data;
    srt->forw=first;
    first->backw=srt;
    first=srt;


}
void insert_last(int data)
{
    node *srt;
    srt=new node();
    srt->info=data;
    last->forw=srt;
    srt->backw=last;
    last=srt;

}
void insert_after(int item,int data)
{
      node *ptr,*srt;
 ptr=new node();
    ptr->info=data;
    srt=first;
    while(srt!=last)
    {
        if(srt->info==item)
        {
            srt->forw->backw=ptr;
             ptr->backw=srt;
              ptr->forw=srt->forw;
            srt->forw=ptr;
            break;

        }else{
        srt=srt->forw;
        }
   }
   if(last->info==item)
   {
       insert_last(data);

   }

}
void insert_before(int item,int data)
{
    node *ptr,*srt;
 ptr=new node();
    ptr->info=data;
    srt=first;
    temp=srt->forw;
       if(first->info==item)
   {
       insert_1st(data);

   }
   else{ while(srt!=last)
    {
        if(temp->info==item)
        {
            ptr->backw=srt;
            ptr->forw=temp;
            temp->backw=ptr;
            srt->forw=ptr;
            break;
        }else{
           srt=srt->forw;
           temp=srt->forw;
        }
    }
   }

}
void forward_traverse()
{
    node *srt;
    srt=first;
    while(srt!=last)
    {
        cout<<srt->info<<" ";
        srt=srt->forw;
    }
    cout<<srt->info<<endl;

}
void backward_traverse()
{
    node *srt;
    srt=last;
    while(srt!=first)
    {
        cout<<srt->info<<" ";
        srt=srt->backw;
    }
    cout<<srt->info<<endl;

}
int main()
{
    int n,data;
    cout<<"Enter the no of element"<<endl;
    cin>>n;
    for(int i=0; i<n; i++)
    {
        cin>>data;
        creat_list(data);
    }
    cout<<"after forward traversing"<<endl;
    forward_traverse();
    cout<<endl;
    cout<<"after backward traversing"<<endl;
    backward_traverse();
    cout<<endl;
    int x,y;
    cout<<"Enter the element"<<endl;
    cin>>x;
    insert_1st(x);
    cout<<"after inserting at first"<<endl;
     forward_traverse();
     cout<<endl;
      cout<<"Enter the element"<<endl;
    cin>>x;
    insert_last(x);
      cout<<"after inserting at last"<<endl;
    forward_traverse();
     cout<<endl;
    cout<<"Enter the position & element"<<endl;
  cin>>x>>y;
    insert_before(x,y);
    cout<<"after inserting "<<endl;
    forward_traverse();
     cout<<endl;
     cout<<"Enter the position & element"<<endl;
      cin>>x>>y;
    insert_after(x,y);
     cout<<"after inserting "<<endl;
    forward_traverse();
     cout<<endl;
}