Point.java

Below is the syntax highlighted version of Point.java from §3.2 Creating Data Types.

/******************************************************************************
 *  Compilation:  javac Point.java
 *  Execution:    java Point
 *
 *  Immutable data type for 2D points.
 *
 ******************************************************************************/

public class Point {
    private final double x;   // Cartesian
    private final double y;   // coordinates

    // creates and initializes a point with given (x, y)
    public Point(double x, double y) {
        this.x = x;
        this.y = y;
    }

    // return the Euclidean distance between the two points
    public double distanceTo(Point that) {
        double dx = this.x - that.x;
        double dy = this.y - that.y;
        return Math.sqrt(dx*dx + dy*dy);
    }

    // draw point using standard draw
    public void draw() {
        StdDraw.point(x, y);
    }

    // draw the line from the invoking point p to q using standard draw
    public void drawTo(Point that) {
        StdDraw.line(this.x, this.y, that.x, that.y);
    }

    // return string representation of this point
    public String toString() {
        return "(" + x + ", " + y + ")";
    }



    // test client
    public static void main(String[] args) {
        Point p = new Point(0.6, 0.2);
        StdOut.println("p  = " + p);
        Point q = new Point(0.5, 0.5);
        StdOut.println("q  = " + q);
        StdOut.println("dist(p, q) = " + p.distanceTo(q));
    }
}