public class Triangle implements Measureable
{
  private double s1;
  private double s2;
  private double s3;

  public Triangle(double a, double b, double c)
  {
    s1 = a;
    s2 = b;
    s3 = c;
  }

  // In the case of a triangle, the "value" is its area.
  // Since we have the sides, we'll use Heron's formula.
  // s = semiperimeter; area = the sqrt of s(s-s1)(s-s2)(s-s3)
  public double getValue()
  {
    double s = (s1 + s2 + s3) / 2;
    return Math.sqrt(s * (s - s1) * (s - s2) * (s - s3));
  }

  // When we want to print a triangle, just list the 3 side lengths.
  public String toString()
  {
    return s1 + "," + s2 + "," + s3;
  }
}