template<class T>
class AbstractTree
{
  T data;
  AbstractTree *left, *right;
public:
  AbstractTree( T &inc ) : left(NULL), right(NULL), data(inc){}

  virtual void setData( const T &d)
  {
    data = d;
  }

  virtual T getData() const
  {
    return data;
  }

  virtual AbstractTree getLeft() const
  {
    return left;
  }

  virtual AbstractTree getRight() const
  {
    return right;
  }

  virtual int addLeft( const AbstractTree *a )
  {
    if(left != NULL){
      return 1;
    }
    left = a;
    return 0;
  }

  virtual int addRight( const AbstractTree *a )
  {
    if(right != NULL){
      return 1;
    }
    right = a;
    return 0;
  }
};