CODEWITHSUNDEEP
javacoordinates
user9285741
user9285741

Reputation:

How to make sure my rectangle in java is a valid rectangle

This is my current program that finds a perimeter of a rectangle given four points. I am doing it for a school project and want to make sure that the lines form a valid rectangle but I don't even know where to start to check for intersecting lines here. How would I do that?

package perimeter;
import java.util.Scanner;
import javafx.geometry.Point2D;

public class Main {

    public static void main(String[] args) {
        Scanner input = new Scanner(System.in);

        System.out.print("Enter point 1's x-, y-coordinates: ");
        double x1 = input.nextDouble();
        double y1 = input.nextDouble();
        System.out.print("Enter point 2's x-, y-coordinates: ");
        double x2 = input.nextDouble();
        double y2 = input.nextDouble(); 
        System.out.print("Enter point 3's x-, y-coordinates: ");
        double x3 = input.nextDouble();
        double y3 = input.nextDouble();
        System.out.print("Enter point 4's x-, y-coordinates: ");
        double x4 = input.nextDouble();
        double y4 = input.nextDouble();
        input.close();

        Point2D p1 = new Point2D(x1, y1); 
        Point2D p2 = new Point2D(x2, y2);       
        Point2D p3 = new Point2D(x3, y3); 
        Point2D p4 = new Point2D(x4, y4);

        double Perimeter = p1.distance(p2) + p2.distance(p3) +
          + p3.distance(p4) + p4.distance(p1);

        System.out.println("The perimeter is " + 
                 Perimeter);
    }
}

Upvotes: 1

Views: 1016

Answers (2)

Yuriy F
Yuriy F

Reputation: 361

If you have a rectangle a, b, c, d, check if the distance between a and c is equal to the distance between b and d. That will verify that the shape is a rectangle

double distance = Math.hypot(x1-x2, y1-y2);

Read the docs here: https://docs.oracle.com/javase/7/docs/api/java/lang/Math.html#hypot%28double,%20double%29

Upvotes: 0

JacekQ.
JacekQ.

Reputation: 21

To get perimeter you have to calculate total distance around rectangle, but I think your question is how to check if it is really rectangle given 4 points. I think best way would be checking if 3 points make a right angle(which 3 point would depend on order of your 4 points) Could help little more if we see some code.

Upvotes: 1

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