Question

Why are obj1 and obj2 printing the same areas? I'm trying to learn about Comparable interface. Couldn't figure it out. the compare to method should print 0, 1, or -1

import java.util.*;

public class RectangleMain {
   public static void main(String [] args) throws CloneNotSupportedException
   {
       /*ComparableRectangleAlsoCloneable obj1 = new ComparableRectangleAlsoCloneable(4, 5);
       ComparableRectangleAlsoCloneable obj2 = (ComparableRectangleAlsoCloneable)obj1.clone();
      
       System.out.println(obj1.toString());
       System.out.println(obj1 == obj2); //false
       System.out.println(obj2.toString());*/
      
       Scanner input = new Scanner(System.in);
       double length = 0.0;
       double width = 0.0;
      
      
       System.out.print("Enter in length: ");
       length = input.nextDouble();
      
       System.out.print("Enter in width: ");
       width = input.nextDouble();
      
      
       ComparableRectangleAlsoCloneable1 obj = new ComparableRectangleAlsoCloneable1();
      
       obj.setLength(length);
       obj.setWidth(width);
      
       ComparableRectangleAlsoCloneable1 obj2 = new ComparableRectangleAlsoCloneable1();
  
       obj2.setLength(20);
       obj2.setWidth(4);
      
       System.out.println(obj.getArea());
       System.out.println(obj2.getArea());
      
      
       System.out.println("obj Compare to obj2: " + obj.compareTo(obj2));
      
       //compare areas and print
       /*if(obj.compareTo(obj2) == 0)
       {
           System.out.println("Both areas are the same.");
       }
       else if (obj.compareTo(obj2) > 0)
       {
           System.out.println("Rectangle 1 area is greater than rectangle 2 area.");
       }
       else
       {
           System.out.println("Rectangle 1 area is less than rectangle 2 area.");
       }*/
      
      
      
      
   }

  
}

public class ComparableRectangleAlsoCloneable1 implements Comparable<ComparableRectangleAlsoCloneable1>
{
   private static double length, width;
  
  

   ComparableRectangleAlsoCloneable1()
   {
       length = 0.0;
       width = 0.0;
   }
  
  
  
   public static void setLength(double l)
   {
       length = l;
   }
  
   public static void setWidth(double w)
   {
       width = w;
   }
  
   public double getLength()
   {
       return length;
   }
  
   public double getWidth()
   {
       return width;
   }
  
   public double getArea()
   {
       return length * width;
   }
  

   public int compareTo(ComparableRectangleAlsoCloneable1 obj)
   {
       if(this.getArea() > obj.getArea())
       {
           return 1;
       }
       else if (this.getArea() < obj.getArea())
       {
           return -1;
       }
       else
       {
           return 0;
       }
   }
  
   //for cloning
/*   @Override
   public Object clone() throws CloneNotSupportedException
   {
       return super.clone();
   }*/

  
   //to string method
   @Override
   public String toString()
   {
       return "Length: " + getLength() + ", Width: " + getWidth() + ", Area: " + getArea();
   }

  
  
}

Answer 1

import java.util.Scanner;

public class RectangleMain {
   public static void main(String[] args) throws CloneNotSupportedException {
       /*
       * ComparableRectangleAlsoCloneable obj1 = new
       * ComparableRectangleAlsoCloneable(4, 5);
       * ComparableRectangleAlsoCloneable obj2 =
       * (ComparableRectangleAlsoCloneable)obj1.clone();
       *
       * System.out.println(obj1.toString()); System.out.println(obj1 ==
       * obj2); //false System.out.println(obj2.toString());
       */

       Scanner input = new Scanner(System.in);
       double length = 0.0;
       double width = 0.0;

       System.out.print("Enter in length: ");
       length = input.nextDouble();

       System.out.print("Enter in width: ");
       width = input.nextDouble();

       ComparableRectangleAlsoCloneable1 obj = new ComparableRectangleAlsoCloneable1();

       obj.setLength(length);
       obj.setWidth(width);
       System.out.println(obj.getArea());

       ComparableRectangleAlsoCloneable1 obj2 = new ComparableRectangleAlsoCloneable1();

       obj2.setLength(5);
       obj2.setWidth(5);

       System.out.println(obj2.getArea());
      
       System.out.println("obj Compare to obj2: " + obj.compareTo(obj2));

   }

}

class ComparableRectangleAlsoCloneable1 implements Comparable<ComparableRectangleAlsoCloneable1> {
   private double length, width;

   ComparableRectangleAlsoCloneable1() {
       length = 0.0;
       width = 0.0;
   }

   public void setLength(double l) {
       length = l;
   }

   public void setWidth(double w) {
       width = w;
   }

   public double getLength() {
       return length;
   }

   public double getWidth() {
       return width;
   }

   public double getArea() {
       return length * width;
   }

   public int compareTo(ComparableRectangleAlsoCloneable1 obj) {
       return new Double(obj.getArea()).compareTo(this.getArea());
   }

   // for cloning
   /*
   * @Override public Object clone() throws CloneNotSupportedException {
   * return super.clone(); }
   */

   // to string method
   @Override
   public String toString() {
       return "Length: " + getLength() + ", Width: " + getWidth() + ", Area: " + getArea();
   }

}

// you have created variables as static because of that for every object has same values because of that your getting the same value

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