#include<stdio.h>
#include<stdlib.h>

struct node{
	int k;
	struct node* prev; 
	struct node* ls;
	struct node* ps;
};
struct node *dodaj_element(struct node *root, struct node* nowy); 
int main(){
struct node *root=NULL; struct node *nowy=NULL; 
root=dodaj_element(root,1);
root=dodaj_element(root,2);
root=dodaj_element(root,3); 


}



struct node *dodaj_element(struct node *root, int n)
{if(root==NULL) 
{root=(struct node*)malloc(sizeof(struct node)); 
root->k=n;
root->prev=NULL;
root->ls=NULL;
root->ps=NULL;
}
else if(n< (root->k))
{if(root->ls!=NULL)
	dodaj_element(n,root->ls);
}
else{
	  struct node *nowy = NULL;
	  nowy=(struct node*)malloc(sizeof(struct node));
      nowy->k = n;
      nowy->ls= NULL;
      nowy->ps = NULL;
      nowy->prev = root;
      root->ls=nowy;
}
}
else{
	 if(root->ps!=NULL)
      {
       dodawanie(n,root->ps);
      }
	 else{
	   node *nowy = (node*)malloc(sizeof *node);
       nowy->k = n;
       nowy->ls = NULL;
       nowy->ps = NULL;
       nowy->prev = start;
       root->ps=nowy;
	 }

}
return root; 
}

void in_order(struct node *root) 
 
{ 
  
if(root->ls != NULL) 
   
in_order(root->ls);   
printf("%dn", root->k); 
 
 
if(root->ps!= NULL)    
in_order(root->ps); 
 
}