/**

* An immutable point in two-dimensional space.

*/

public class Point {

public static final double DELTA = 0.001;

private final double x;

private final double y;

/**

* Constructs a point at the given location.

*

* @param x the X coordinate

* @param y the Y coordinate

*/

public Point(double x, double y) {

this.x = x;

this.y = y;

}

/**

* @return the X coordinate

*/

public double getX() {

return x;

}

/**

* @return the Y coordinate

*/

public double getY() {

return y;

}

/**

* Computes the distance between two points.

*

* @param pt the other point

* @return Euclidean distance

*/

public double distance(Point pt) {

double dx = this.x - pt.x;

double dy = this.y - pt.y;

return Math.sqrt(dx * dx + dy * dy);

}

/**

* Determines whether or not two points are equal.

*

* @param obj the other point

* @return true if this equals obj

*/

public boolean equals(Object obj) {

if (obj instanceof Point) {

Point pt = (Point) obj;

return distance(pt) < DELTA;

}

return super.equals(obj);

}

/**

* @return string representation of the point

*/

public String toString() {

return String.format("(%.1f, %.1f)", this.x, this.y);

}

}