/*
 *
 * 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!");
		}

	}

}