Search:

Please add System.out.println after each assignment ie
b3=b1+b2; //Line 1
System.out.println( " Value of b3 now "+b3);
by the way I noticed following compilation error with your program ...did...

To address your question "I am still confused on what the are actually good for."
Interfaces are only option when you want to implement Mutiple Inheritence in Java which is not possible by using...

1 suggestion that will help you help earn money too. Teach 10th and 12th Standard Students Java 1st this will help you to brush up all your coding skills at beginner level.Next check if you can act...