// CSE 142 Winter 2008, Marty Stepp
// This file describes a new type of objects named Point.
//
// This second version includes constructors and more methods.

public class Point {
	// fields (data inside each Point object)
	
	int x;     // each Point object has two ints inside it:
	int y;     // x and y.
	
	
	// constructors (initializes the state of each Point object)
	
	// Creates a new Point at the given x/y coordinates.
	// common bug: writing 'void' return type
	// common bug: mis-initializing fields (startingX = x;   int x = startingX;)
	public Point(int startingX, int startingY) {
		x = startingX;
		y = startingY;
	}
	
	// Creates a new Point at the origin, (0, 0).
	public Point() {
		x = 0;
		y = 0;
	}
	
	
	// methods (behavior inside each Point object)
	
	// Returns the distance between this Point and the given other Point.
	public double distance(Point p2) {
		// a^2 + b^2 = c^2
		int dx = x - p2.x;
		int dy = y - p2.y;
		double d = Math.sqrt(dx*dx + dy*dy);
		return d;
	}
	
	// Returns the distance between this Point and the origin, (0, 0).
	public double distanceFromOrigin() {
		// Point origin = new Point();
		// double d = distance(origin);
		// return d;
		return distance(new Point());
	}
	
	
	// Adjusts this Point object's location by the given amounts.
	public void translate(int dx, int dy) {
		// This code runs inside a particular Point object.
		// (We say the code runs "in the context of" that object.)
		// The code knows which object that is,
		// and it knows how to access or change that object's fields.

		this.x = this.x + dx;    // change "this" Point's x
		this.y = this.y + dy;    // change "this" Point's y
	}
}