class List  // I want to use 1 prgram file for this example
{
   int value;
   List next;
}

public class demo
{
   public static void main(String[] args)
   {
      List head = null;    // Empty list
      List p;

      /* -------------------------------------------------
         Create a list element and insert in List at head
         ------------------------------------------------- */
      for( int i=1; i <= 10; i++ )
      {
         p = new List( );
         p.value = i;
         head = insert(head, p);       // Insert p in head
         print(head);
      } 
   }

   /* =========================================
      insert(h, e): insert e at tail of list h
                    return new list

      A List variable is a reference variable !!!
      ========================================= */
   public static List insert( List head, List e )
   {
      /* --------------------------------------------
          Base case: insert at the tail of an empty
         -------------------------------------------- */
      if ( head == null )
      {
         e.next = null;     // Mark e as the last list elem
         return(e);         // e is the first list elem !
      }
      else
      {
         /* ===========================================================
            Solve the problem USING the solution of a smaller problem
            =========================================================== */
         head.next = insert( head.next, e ); // Link directly to helpSol

         return head;             // Return MY solution
      }
   } 

   // Print the list
   public static void print(List h)
   {
      while (h != null)
      {
         System.out.printf("%d ", h.value);
         h = h.next;
      }
      System.out.printf("\n\n");
   }
}
   

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

struct List       // This is the List class definition in C
{
   int          value;
   struct List *next;
};

struct List *insert( struct List *head, struct List *e ); 
void print(struct List *h); 

void main(int argc, char *argv[])
{
   struct List *head = NULL;   // Nul pointer NULL instead of null
   struct List *p;

   /* -------------------------------------------------
      Create a list element and insert in List at head
      ------------------------------------------------- */
   for ( int i=1; i <= 4; i++ )
   {
      p = malloc( sizeof(struct List) );
      p->value = i;
      head = insert(head, p);       // Insert p in head
      print(head);
   }
}

/* =======================================================
   insert(head, e): insert at tail
   ======================================================= */
struct List *insert( struct List *head, struct List *e )
{
   /* --------------------------------------------
       Base case: insert at the tail of an empty
      -------------------------------------------- */
   if ( head == NULL )
   {
      e->next = NULL;   // Mark e as the last list elem
      return(e);         // e is the first list elem !
   }
   else
   {
      /* ===========================================================
         Solve the problem USING the solution of a smaller problem
         =========================================================== */
      head->next = insert( head->next, e ); // Link directly to helpSol

      return head;             // Return MY solution
   }
}

// Print the list
void print(struct List *h)
{
   while (h != NULL)
   {
      printf("%d ", h->value);
      h = h->next;
   }
   printf("\n\n");
}