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Point3D

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Author: Robert Baxter

You have been asked to extend the Point class that represents 2-D (x, y) coordinates. The Point class includes the following public constructors and methods:

Method/Constructor Description
public Point() constructs the point (0, 0)
public Point(int x, int y) constructs a point with the given x/y coordinates
public void setLocation(int x, int y) sets the coordinates to the given values
public int getX() returns the x-coordinate
public int getY() returns the y-coordinate
public String toString() returns String in standard "(x, y)" notation
public double distanceFromOrigin() returns the distance from the origin (0, 0) computed as the square root of (x2 + y2)

You are to define a new class called Point3D that extends this class through inheritance. It should behave like a Point except that it should be a 3-dimensional point that keeps track of a z-coordinate. You should provide the same methods as the superclass, as well as the following new behavior:

Method/Constructor Description
public Point3D() constructs the point (0, 0, 0)
public Point3D(int x, int y, int z) constructs a point with the given x/y/z coordinates
public void setLocation(int x, int y, int z) sets the coordinates to the given values
public int getZ() returns the z-coordinate

Some of the existing behaviors from Point should behave differently on Point3D objects:

  • When the original 2-parameter version of the setLocation is called, the 3-D point's x/y coordinates should be set as specified, and the z-coordinate should be set to 0.
  • When a 2-D point is printed with toString, it should be returned in an "(x, y, z)" format that shows all three coordinates.
  • A 3-D point's distance from the origin is computed using all three coordinates, it is equal to the square root of (x2 + y2 + z2).

You must also make Point3D objects comparable to each other using the Comparable interface. 3-D points are compared by x-coordinate, then by y-coordinate, then by z-coordinate. In other words, a Point3D object with a smaller x-coordinate is considered to be "less than" one with a larger x-coordinate. If two Point3D objects have the same x-coordinates, the one with the lower y-coordinate is considered "less". If they have the same x and y-coordinates, the one with the lower z-coordinate is considered "less". If the two points have the same x, y, and z-coordinates, they are considered to be "equal".

Type your solution here:


This is an inheritance problem. Write a Java class using inheritance. (You do not need to write any import statements.)

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