Re: Cannot debug this code !!!

From:

ankur <ankur.a.agarwal@gmail.com>

Newsgroups:

comp.lang.java.programmer

Date:

Sat, 8 Dec 2007 21:26:45 -0800 (PST)

Message-ID:

<ad24e2ed-fce8-40b5-8d67-b68da896b0a1@d27g2000prf.googlegroups.com>

Cool. You nailed it. I added a return -2 after both the if blocks.
But I am surprised about one thing. I am using eclipse. Why is the
code for Circle.java bothered about conditions it hasn't yet
encountered. I mean I am sending it a rectangle and circle and have
written a code to deal with it. So why get an error when I am not
sending it any third type of object ??

Ankur
On Dec 8, 8:43 pm, Kira Yamato <kira...@earthlink.net> wrote:

On 2007-12-08 23:35:31 -0500, ankur <ankur.a.agar...@gmail.com> said:

public interface MyComparable {
   int compareTo(Object obj);
}

public class Rectangle {
   public double width;
   public double length;

   public Rectangle(double w, double l)
   {
           width = w;
           length = l;
   }

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

public class Circle implements MyComparable {
   private double radius;
   public Circle ( double r)
   {
           radius = r;
   }
   public double area()

   {
           return 3.1416*radius*radius;
   }

   public int compareTo(Object obj)
   {
           if (obj instanceof Rectangle)
           {

                   Rectangle rec = (Rectangle)obj;
                   if ( this.area() < rec.area())
                           {
                                   return -1;
                           }
                   else
                           if ( this.area() > rec.area())
                                   {
                                           return 1;
                                   }
                           else
                                   {
                                           return 0;
                                   }
           }

           if (obj instanceof Circle)
           {
                   Circle cir = (Circle)obj;
                   if ( this.area() < cir.area())
                           {
                                   return -1;
                           }
                   else if ( this.area() > cir.area())
                           {
                                   return 1;
                           }
                           else
                           {
                                   return 0;
                           }
           }
   }

What happens if obj is neither Rectangle nor Circle?

}

public class TestComparable {

   public static void main(String[] args) {
           Circle cir = new Circle(4.5);
           Rectangle rec = new Rectangle(3,4);

           int res = -2;

           res = cir.compareTo(rec);
           System.out.printf("The result is %d", res);

   }

}

I get an error message :

Exception in thread "main" java.lang.Error: Unresolved compilation
problem:
   This method must return a result of type int

   at Circle.compareTo(Circle.java:14)
   at TestComparable.main(TestComparable.java:10)

Can you help ??

Thanks,
Ankur

--

-kira