// Marty Stepp, CSE 142, Autumn 2008
// This file defines a new class of objects named Point.
//
// All the code in the class's {} braces represents what contents
// should be replicated inside of each Point object.  This includes the methods
// written today: each Point object has a copy of each method that can access
// that Point object's fields.
//
// This version of the class adds the following features:
//     - constructor (initializes new Point objects)
//     - toString method (tells Java how to println Point objects)
//     - encapsulation (private fields to protect the object's data)
//

import java.awt.*;  // for Graphics

public class Point {
	// encapsulation - only Point objects can access their own fields directly
	private int x;    // EACH Point object should have a variable
	private int y;    // inside it named x, and a variable named y
	
	// Initializes the state of a new Point object at the given x/y location.
	// 1) run when client says 'new'
	// 2) initializes the state of the object being created
	public Point(int initialX, int initialY) {
		x = initialX;
		y = initialY;
	}
	
	// Initializes the state of a new Point object at the origin (0, 0).
	public Point() {
		x = 0;
		y = 0;
	}
	
	// Returns the point's x-coordinate.
	// Provides a read-only access to the point's state.
	public int getX() {
		return x;
	}
	
	// Returns the point's y-coordinate.
	public int getY() {
		return y;
	}

	// Draws a point on a DrawingPanel.
	public void draw(Graphics g) {
		g.fillOval(x, y, 3, 3);
		g.drawString(toString(), x, y);
	}
	
	// Shifts the point's x/y coordinates by the given amounts.
	public void translate(int dx, int dy) {
		x += dx;
		y += dy;    // or, setLocation(x + dx, y + dy);
	}
	
	// Sets the point's x/y coordinates to be the given values.
	public void setLocation(int newX, int newY) {
		x = newX;
		y = newY;
	}
	
	// Computes the distance between this point and the given other point p2.
	public double distance(Point p2) {
		int dx = x - p2.x;
		int dy = y - p2.y;
		double distance = Math.sqrt(dx*dx + dy*dy);
		return distance;
	}
	
	// Computes the distance between this point and the origin (0, 0).
	public double distanceFromOrigin() {
		Point origin = new Point();  // 0, 0
		return distance(origin);
	}
	
	// Returns a string representation of the point, such as "(5, -2)".
	public String toString() {
		return "(" + x + ", " + y + ")";
	}
}