/*
 *
 * a data structure that represents a 2d point
 *
 */


class Point
{
  private double x;
  private double y;

  // method: two-argument constructor
  //     in: doubles x and y
  //    out: a new Point
  public Point(double x_in, double y_in)
  {
    this.x = x_in;
    this.y = y_in;
  }

  // method: zero-argument constructor
  //     in: no inputs
  //    out: a new Point (at the origin)
  public Point() // a zero-input constructor!
  {
    this.x = 0.0;
    this.y = 0.0;
  }

  // method: equals
  //     in: a Point, p
  //    out: a boolean, whether or not this and p are the same Point
  public boolean equals(Point p)
  {
    if ( this.x == p.x  &&  this.y == p.y )
      return true;
    else
      return false;
  }

  // method: toString
  //     in: none
  //    out: a String representation of this Point
  public String toString()
  {
    String s = "(" + this.x + "," + this.y + ")";
    return s;
  }  

  // method: add
  //     in: a Point, p
  //    out: a new Point that is the sum of this and p
  public Point add( Point p )
  {
    return new Point( this.x + p.x, this.y + p.y );
  }

  // method: scale
  //     in: a double, d, the factor by which to scale
  //    out: a new Point that is a scaled version of this
  public Point scale(double d)
  {
    return new Point( d* this.x, d*this.y );
  }

  // method: isSmaller
  //     in: a Point, p
  //    out: whether or not this is closer to the origin than p
  public boolean isSmaller(Point p)
  {
    // could be more concise, but it's not bad to 
    // see how to call Math functions
    // the Java API lists them all (Google for "Java 1.6 API")
    double magThis = Math.sqrt( this.x*this.x + this.y*this.y );
    double magOfp  = Math.sqrt( p.x*p.x + p.y*p.y );
    return ( magThis < magOfp );
  }
    
  // method: main
  //     in: usual stuff, ignored as usual
  //    out: nothing (a void function)
  // ** printing stuff is quite different from returning stuff! **
  public static void main(String[] args)
  {
    Point p1 = new Point(30, 40);
    Point p2 = new Point(12,  2);
    Point p3 = p1.add( p2 );

    System.out.println("p1 is " + p1);
    System.out.println("p2 is " + p2);
    System.out.println("p3 (sum) is " + p3);

    Point p4 = p1.scale( 0.5 );
    System.out.println("p4 is " + p4);
    
    if (p2.isSmaller(p1))
        System.out.println("p2 IS smaller than p1.");
    else
        System.out.println("p2 is NOT smaller than p1!");

  }

}