package funpoly;

import funpoly.visitor.IVisitor;

/**
* Represents the non-constant polynomial type.  Holds a postive degree (or order)
* and a polynomial of lower order.
* @author Dung X. Nguyen
*/
class NonConstPoly extends APolynomial
{
   /**
   * Data Invariant: 0 < _degree.
   */
	private int _degree;

   /**
	 * Data Invariant: _lowerPoly._degree < _degree.
	 * @SBGen Variable (,lower order polynomial,,64)
	 */
	private APolynomial _lowerPoly;

	/**
	 * @param coef the coefficient
	 * @param degree the degree, > 0.
	 * @param lowPoly the lower ordered polynomial.
	 */
	NonConstPoly(int coef, int degree, APolynomial lowPoly)
	{
      _coef = coef;
      _degree = degree;
      _lowerPoly = lowPoly;
	}

	public int getDegree()
	{
		return _degree;
	}

	public APolynomial getLowerPoly()
	{
		return _lowerPoly;
	}

   public String toString ()
   {
      return Integer.toString(_coef) + "x^" + Integer.toString(_degree) +_lowerPoly.toStringHelp();
   }

   String toStringHelp ()
   {
      return " + " + toString ();
   }

   /**
   * Calls algo.forNonConst (...).
   */
	public Object execute(IVisitor algo, Object input)
	{
		return algo.forNonConst (this, input);
	}
}