// An example of method overloading
//
public class Calculator
{
  // 3 versions of the area method
  // to deal with 3 possible types
  public double area(Square s)
  {
    return s.size*s.size;
  }
  public double area(Triangle t)
  {
    double areaTri;
    areaTri = 1./2.*Math.abs( (t.x[1]-t.x[0])*(t.y[2]-t.y[0])-
                              (t.y[1]-t.y[0])*(t.x[2]-t.x[0]) );
    return areaTri;
  }
  public double area(Circle c)
  {
    return c.radius*c.radius*Math.PI;
  }
}