#include <library.h>

/*
   what does this function do?
   how can we understand it?

   Find a simple case. If Q is zero it is trivial
      to work out, N being less than 10 makes Q zero.
   Now we know exactly what thing(X) does if X < 10

   That means that if Q < 10, we'll always know what
   it does, N being less than 100 makes Q less than 10.
   Now we know exactly what thing(X) does if X < 100

   keep on building knowledge up based on what you have
   already worked out, and soon you know exactly what
   thing does in all circumstances
*/

void thing(const int N)
{ const int Q = N / 10,
            R = N % 10;
  print(R);
  if (Q > 0)
    thing(Q);
  print(R); }

void main()
{ thing(3);
  new_line();
  thing(37);
  new_line();
  thing(375);
  new_line();
  thing(3758);
  new_line();
  thing(37582);
  new_line();
  thing(375824);
  new_line(); }