Java

OOP GUIDE / WORK

POINT CLASS 2

TASK – PART 1 – CONSIDER THE FOLLOWING POINT CLASS

No work

TASK – PART 2 – TESTING THE POINT CLASS

Here is my Tester class:

public class PointTester

{

public static void main(String[] args)

{

Point p1 = new Point(4,6);

Point p2 = new Point(7,3);

double d1 = p1.distanceFrom(p2.x, p2.y);

System.out.println(d1);

double d2 = p2.distanceFrom(p1.x, p1.y);

System.out.println(d2);

}

}

Note: Both d1 and d2 get the value 4.24.

TASK – PART 3 – ADDING A NEW METHOD

Here is my method:

public double distanceFrom(Point q)

{

double dx = q.x - this.x;

double dy = q.y - this.y;

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

}

Note: A shorter solution would have been to simply call the other distanceFrom method.

TASK – PART 4 – MORE TESTING

Here is the code I added to the tester class to test the new method:

double d3 = p1.distanceFrom(p2);

System.out.println(d1);

double d4 = p2.distanceFrom(p1);

System.out.println(d2);

TASK – PART 5 – PROCESSING A POINT ARRAY

Here is the code I added to the PointTester class:

public class PointTester

{

public static void main(String[] args)

{

Point[] polygon = new Point[9];

polygon[0] = new Point(0, 0);

polygon[1] = new Point(3, 2);

polygon[2] = new Point(4, 1);

polygon[3] = new Point(3, 5);

polygon[4] = new Point(6, 3);

polygon[5] = new Point(5, 8);

polygon[6] = new Point(3, 9);

polygon[7] = new Point(2, 6);

polygon[8] = new Point(1, 2);

//Add your code here.

double totalDistance = polygon[0].distanceFrom(polygon[8]);

for (int i=0; i<polygon.length-1; i++)

{

totalDistance += polygon[i].distanceFrom(polygon[i+1]);

}

System.out.println("Perimeter: " + totalDistance); }

}

Note: Perimeter is 29.6.