Question

Requirements:   You are to write a class called Point – this will represent a geometric point in a Cartesian plane (but x and y should be ints).   Point should have the following:

Data:  

• that hold the x-value and the y-value. They should be ints and must be private.

Constructors:

• A default constructor that will set the values to (2,-7)

• A parameterized constructor that will receive 2 ints (x then y) and set the data to what is received.

• A copy constructor that will receive a Point. If it receives null, then it should

throw new IllegalArgumentException(<”your meaningful String here”>);

If it is OK, the it should initialize the data (of the new instance being created) to be the same as the Point that was received.

Methods:

• The methods to be implemented are shown in the PointInterface.java. You can look at this file to see the requirements for the methods.

• Your Point class should be defined like this:

public class Point implements PointInterface

When your Point.java compiles, Java will expect all methods in the interface to be implemented and will give a compiler error if they are missing. The compiler error will read “class Point is not abstract and does not implement method ”.

You can actually copy the PointInterface methods definitions into your Point class so it will have the comments and the method headers.   If you do this, be sure to take out the ; in the method headers or you will get a “missing method body” syntax error when compiling…

• But a toString() method and a .equals(Object obj) method are automatically inherited from the Object class. So if you do not implement them, Java will find and use the inherited ones – and will not give a compiler error (but the inherited ones will give the wrong results). The Point class should have its own .toString and .equals methods.
• ==============================================================================
• This is the interface (called PointInterface.Java) for a Point class (which will represent a 2-dimensional Point)

• public interface PointInterface

  {

  // toString

  // returns a String representing this instance in the form (x,y)

  (WITHOUT a space after the ,)

  public String toString();

  // distanceTo

  // throws a new IllegalArgumentException(

  if null is received

  // returns the distance from this Point to the Point that was

  received

  // NOTE: there is a static method in the Math class called hypot

  can be useful for this method

  public double distanceTo(Point otherPoint);

  //equals - returns true if it is equal to what is received (as an Object)

  public boolean equals(Object obj);

  // inQuadrant

  // returns true if this Point is in the quadrant specified

  // throws a new IllegalArgumentException if the quadrant is

  out of range (not 1-4)

  public boolean inQuadrant(int quadrant);

  // translate

  // changes this Point's x and y value by the what is received (thus

  "translating" it)

  // returns nothing

  public void translate(int xMove, int yMove);

  // onXAxis

  // returns true if this Point is on the x-axis

  public boolean onXAxis();

  // onYAxis

  // returns true if this Point is to the on the y-axis

  public boolean onYAxis();

  //=============================================

  // The method definitions below are commented out and

  // do NOT have to be implemented

  // //===========================================

  // halfwayTo

  // throws a new IllegalArgumentException(

  if null is received

  // returns a new Point which is halfway to the Point that is

  received

  //public Point halfwayTo(Point another);

  // slopeTo

  // throws a new IllegalArgumentException(

  if null is received

  // returns the slope between this Point and the one that is

  received.

  // since the slope is (changeInY/changeInX), then first check to see if

  changeInX is 0

  // if so, then return Double.POSITIVE_INFINITY; (since the

  denominator is 0)

  //public double slopeTo(Point anotherPoint)

  }
  
  

Answer 1

/****************************Point.java*****************************/

public class Point implements PointInterface {

   private int x;
   private int y;

   public Point() {

       this.x = 2;
       this.y = -7;
   }

   public Point(int x, int y) {
       super();
       this.x = x;
       this.y = y;
   }

   public Point(Point p) throws InvalidArgumentException {

       if (p == null) {

           throw new InvalidArgumentException("Null pointer exception!");
       } else {

           this.x = p.x;
           this.y = p.y;
       }
   }

   @Override
   public double distanceTo(Point otherPoint) {

       if (this == null || otherPoint == null) {

           throw new IllegalArgumentException();
       }
       return Math.sqrt(Math.pow((otherPoint.x - this.x), 2) + Math.pow((otherPoint.y - this.y), 2));
   }

   @Override
   public boolean inQuadrant(int quadrant) {

       if (quadrant==0||quadrant>4) {
                          
           throw new IllegalArgumentException();
       } else if (quadrant(this.x, this.y) == quadrant) {
           return true;
       }

       return false;
   }

   private static int quadrant(int x, int y) {
       if (x > 0 && y > 0) {
           return 1;
       } else if (x < 0 && y > 0) {
           return 2;
       } else if (x < 0 && y < 0) {
           return 3;
       } else if (x > 0 && y < 0) {
           return 4;
       } else {

           return 0;
       }
   }

   @Override
   public void translate(int xMove, int yMove) {

       this.x = x + xMove;
       this.y = y + yMove;

   }

   @Override
   public boolean onXAxis() {

       if (this.y == 0) {

           return true;
       }
       return false;
   }

   @Override
   public boolean onYAxis() {

       if (this.x == 0) {

           return true;
       }
       return false;
   }

   @Override
   public String toString() {
       return "Point [x=" + x + ", y=" + y + "]";
   }

   @Override
   public boolean equals(Object arg0) {

       if (this == null || (Point) arg0 == null) {
           throw new IllegalArgumentException("");
       }
       if (this.x == ((Point) arg0).x && this.y == ((Point) arg0).y) {

           return true;
       } else {

           return false;
       }
   }

}

/*********************output*******************/

testing all

-----------------------------

==>Testing parameterized constructor/toString(): passing in -1 and -3
Point [x=-1, y=-3]

==>Testing parameterized constructor/toString(): passing in -1 and 4
Point [x=-1, y=4]

==>Testing parameterized constructor/toString(): passing in 0 and -3
Point [x=0, y=-3]

==>Testing parameterized constructor/toString(): passing in 0 and 4
Point [x=0, y=4]

==>Testing parameterized constructor/toString(): passing in 6 and -3
Point [x=6, y=-3]

==>Testing parameterized constructor/toString(): passing in 6 and 4
Point [x=6, y=4]

-----------------------------

==>Testing default constructor/toString()
Point [x=2, y=-7]

-----------------------------

==>Testing copy constructor (translate must work), passing in null
InvalidArgumentException

==>Testing copy constructor (translate must work), passing in Point [x=5, y=6]
Point that was created is: Point [x=5, y=6]

-----------------------------

==>Testing Point [x=-3, y=4] 's .translate(0, 0)
Point [x=-3, y=4]

==>Testing Point [x=-3, y=4] 's .translate(0, 7)
Point [x=-3, y=11]

==>Testing Point [x=-3, y=4] 's .translate(5, 0)
Point [x=2, y=4]

==>Testing Point [x=-3, y=4] 's .translate(5, 7)
Point [x=2, y=11]

-----------------------------

==>Testing Point [x=0, y=0] 's .inQuadrant(0)
true

==>Testing Point [x=0, y=6] 's .inQuadrant(0)
true

==>Testing Point [x=0, y=-2] 's .inQuadrant(0)
true

==>Testing Point [x=-3, y=0] 's .inQuadrant(0)
true

==>Testing Point [x=-3, y=6] 's .inQuadrant(0)
false

==>Testing Point [x=-3, y=-2] 's .inQuadrant(0)
false

==>Testing Point [x=5, y=0] 's .inQuadrant(0)
true

==>Testing Point [x=5, y=6] 's .inQuadrant(0)
false

==>Testing Point [x=5, y=-2] 's .inQuadrant(0)
false

==>Testing Point [x=0, y=0] 's .inQuadrant(1)
false

==>Testing Point [x=0, y=6] 's .inQuadrant(1)
false

==>Testing Point [x=0, y=-2] 's .inQuadrant(1)
false

==>Testing Point [x=-3, y=0] 's .inQuadrant(1)
false

==>Testing Point [x=-3, y=6] 's .inQuadrant(1)
false

==>Testing Point [x=-3, y=-2] 's .inQuadrant(1)
false

==>Testing Point [x=5, y=0] 's .inQuadrant(1)
false

==>Testing Point [x=5, y=6] 's .inQuadrant(1)
true

==>Testing Point [x=5, y=-2] 's .inQuadrant(1)
false

==>Testing Point [x=0, y=0] 's .inQuadrant(2)
false

==>Testing Point [x=0, y=6] 's .inQuadrant(2)
false

==>Testing Point [x=0, y=-2] 's .inQuadrant(2)
false

==>Testing Point [x=-3, y=0] 's .inQuadrant(2)
false

==>Testing Point [x=-3, y=6] 's .inQuadrant(2)
true

==>Testing Point [x=-3, y=-2] 's .inQuadrant(2)
false

==>Testing Point [x=5, y=0] 's .inQuadrant(2)
false

==>Testing Point [x=5, y=6] 's .inQuadrant(2)
false

==>Testing Point [x=5, y=-2] 's .inQuadrant(2)
false

==>Testing Point [x=0, y=0] 's .inQuadrant(3)
false

==>Testing Point [x=0, y=6] 's .inQuadrant(3)
false

==>Testing Point [x=0, y=-2] 's .inQuadrant(3)
false

==>Testing Point [x=-3, y=0] 's .inQuadrant(3)
false

==>Testing Point [x=-3, y=6] 's .inQuadrant(3)
false

==>Testing Point [x=-3, y=-2] 's .inQuadrant(3)
true

==>Testing Point [x=5, y=0] 's .inQuadrant(3)
false

==>Testing Point [x=5, y=6] 's .inQuadrant(3)
false

==>Testing Point [x=5, y=-2] 's .inQuadrant(3)
false

==>Testing Point [x=0, y=0] 's .inQuadrant(4)
false

==>Testing Point [x=0, y=6] 's .inQuadrant(4)
false

==>Testing Point [x=0, y=-2] 's .inQuadrant(4)
false

==>Testing Point [x=-3, y=0] 's .inQuadrant(4)
false

==>Testing Point [x=-3, y=6] 's .inQuadrant(4)
false

==>Testing Point [x=-3, y=-2] 's .inQuadrant(4)
false

==>Testing Point [x=5, y=0] 's .inQuadrant(4)
false

==>Testing Point [x=5, y=6] 's .inQuadrant(4)
false

==>Testing Point [x=5, y=-2] 's .inQuadrant(4)
true

==>Testing Point [x=0, y=0] 's .inQuadrant(8)
false

==>Testing Point [x=0, y=6] 's .inQuadrant(8)
false

==>Testing Point [x=0, y=-2] 's .inQuadrant(8)
false

==>Testing Point [x=-3, y=0] 's .inQuadrant(8)
false

==>Testing Point [x=-3, y=6] 's .inQuadrant(8)
false

==>Testing Point [x=-3, y=-2] 's .inQuadrant(8)
false

==>Testing Point [x=5, y=0] 's .inQuadrant(8)
false

==>Testing Point [x=5, y=6] 's .inQuadrant(8)
false

==>Testing Point [x=5, y=-2] 's .inQuadrant(8)
false

-----------------------------

==>Testing whether Point [x=4, y=-2] .equals null
java.lang.IllegalArgumentException

==>Testing whether Point [x=4, y=-2] .equals Point [x=4, y=-2] (as a STRING)
java.lang.ClassCastException

==>Testing whether Point [x=4, y=-2] .equals Point [x=4, y=1]
false

==>Testing whether Point [x=4, y=-2] .equals Point [x=9, y=-2]
false

==>Testing whether Point [x=4, y=-2] .equals Point [x=11, y=0]
false

==>Testing whether Point [x=4, y=-2] .equals Point [x=4, y=-2]
true

==>Testing whether Point [x=4, y=-2] .equals Point [x=-2, y=4]
false

-----------------------------

==>Testing Point [x=6, y=9] 's .distanceTo null
java.lang.IllegalArgumentException

==>Testing Point [x=-1, y=5] 's .distanceTo Point [x=-1, y=5]
0

==>Testing Point [x=-1, y=5] 's .distanceTo Point [x=-1, y=2]
3

==>Testing Point [x=-1, y=5] 's .distanceTo Point [x=5, y=5]
6

==>Testing Point [x=-1, y=5] 's .distanceTo Point [x=5, y=2]
6.708

==>Testing Point [x=-1, y=2] 's .distanceTo Point [x=-1, y=5]
3

==>Testing Point [x=-1, y=2] 's .distanceTo Point [x=-1, y=2]
0

==>Testing Point [x=-1, y=2] 's .distanceTo Point [x=5, y=5]
6.708

==>Testing Point [x=-1, y=2] 's .distanceTo Point [x=5, y=2]
6

==>Testing Point [x=5, y=5] 's .distanceTo Point [x=-1, y=5]
6

==>Testing Point [x=5, y=5] 's .distanceTo Point [x=-1, y=2]
6.708

==>Testing Point [x=5, y=5] 's .distanceTo Point [x=5, y=5]
0

==>Testing Point [x=5, y=5] 's .distanceTo Point [x=5, y=2]
3

==>Testing Point [x=5, y=2] 's .distanceTo Point [x=-1, y=5]
6.708

==>Testing Point [x=5, y=2] 's .distanceTo Point [x=-1, y=2]
6

==>Testing Point [x=5, y=2] 's .distanceTo Point [x=5, y=5]
3

==>Testing Point [x=5, y=2] 's .distanceTo Point [x=5, y=2]
0

Please let me know if you have any doubt or modify the answer, Thanks :)

2 Console X <terminated Point TesterHG [Java Application) C:\Program Files Java jre1.8.0_211\bin\javaw.exe (Sep 24, 2019, 7:11:18 AM) testing all and 3 ==>Testing parameterized constructor/toString(): passing in -1 Point [x=-1, y=-3] ==>Testing parameterized constructor/toString(): passing in -1 Point (x=-1, y=4] and 4 ==>Testing parameterized constructor/toString(): passing in Point (x=0, y=-3] and -3 and 4 ==> Testing parameterized constructor/toString(): passing in Point (x=0, y=4] ==> Testing parameterized constructor/toString(): passing in 6 and -3, Point (x=6, y=-3] ==>Testing parameterized constructor/toString(): passing in 6 and 4 Point [x=6, y=4] --------- ==>Testing default constructor/toString() Point (x=2, y=-7] ==>Testing copy constructor (translate must work), passing in null InvalidArgumentException ==> Testing copy constructor (translate must work), passing in Point [x=5, y=6] Point that was created is: Point [x=5, y=6] ==> Testing Point [x=-3, y=4] 's .translate(0, 0) Point [x=-3, y=4] ==>Testing Point [x=-3, y=4] 's translate(0, 7) Point (x=-3, y=11] ==>Testing Point (=-3, y=4] 's .translate(5, 0) Point [x=2, y=4]