Question

Java question: I need to fix a point class (code below) Thank you!

/**
 * A point, implemented as a location without a shape.
 */
public class Point extends Location {

   // TODO your job
   // HINT: use a circle with radius 0 as the shape!

   public Point(final int x, final int y) {
      super(-1, -1, null);
      assert x >= 0;
      assert y >= 0;
   }
}

Answer 1

import java.util.Objects;

public final class Point {
    private  double x;    // x-coordinate
    private  double y;    // y-coordinate

    // no parameter constructor to generate random point
    public Point() {
        x = (Math.random() * (1.0 - 0.0 + 1) + 0.0);
        y = (Math.random() * (1.0 - 0.0 + 1) + 0.0);
    }

    // parameterized constructor
    public Point(double x, double y) {
        this.x = x;
        this.y = y;
    }

    // getters
    public double getX() { return x; }
    public double getY() { return y; }

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

    @Override
    public boolean equals(Object o) {
        if (this == o) return true;
        if (o == null || getClass() != o.getClass()) return false;
        Point point = (Point) o;
        return Double.compare(point.x, x) == 0 &&
                Double.compare(point.y, y) == 0;
    }

    @Override
    public int hashCode() {
        return Objects.hash(x, y);
    }

    public String toString() {
        return "(" + x + ", " + y + ")";
    }



    // driver method
    public static void main(String[] args) {
        Point p1 = new Point();
        System.out.println("p  = " + p1);
        System.out.println("   x     = " + p1.getX());
        System.out.println("   y     = " + p1.getY());
        System.out.println();

        Point p2 = new Point(0.5, 0.5);
        System.out.println("q  = " + p2);
        System.out.println("   x     = " + p2.getX());
        System.out.println("   y     = " + p2.getY());
        System.out.println("dist(p, q) = " + p1.distanceTo(p2));

        //prints point p1 equals p2 or not
        System.out.println("Is p1 point equals p2 point? " + p1.equals(p2));
    }
}

Output:

p = (0.8087211080759387, 1.0236249374819213)
x = 0.8087211080759387
y = 1.0236249374819213

q = (0.5, 0.5)
dist(p, q) = 0.6078583697906786

Summary:

Above program is written to represent a point by taking x and y coordinates. x and y are made private so that they are no manipulated outside the Point class.

Point class contains two different constructor one parameterized constructor to create point based on the x and y values provided and another no parameter constructor to generate random point.

In main method p1 point is generated randomly and p2 is user defined point as we are setting x and y coordinates manually.

Point class also has distanceTo method to get the distance between 2 points.