/**
   A triangular shape composed of stacked unit squares like this:
   []
   [][]
   [][][]
   . . .
*/
public class Triangle
{
   private int width;

   /**
      Constructs a triangular shape.
      @param aWidth the width (and height) of the triangle
   */
   public Triangle(int aWidth)
   {
      width = aWidth;
   }

   /**
      Computes the area of the triangle.
      @return the area
   */
   public int getArea()
   {
      if (width <= 0) { return 0; }
      else if (width == 1) { return 1; }
      else 
      {
         Triangle smallerTriangle = new Triangle(width - 1);
         int smallerArea = smallerTriangle.getArea();
         return smallerArea + width;
      }
   }
}

