invalid new-expression of abstract class type 'box'
There is nothing unclear about the error message. Your class
box has at least one member that is not implemented, which means it is abstract. You cannot instantiate an abstract class.
If this is a bug, fix your box class by implementing the missing member(s).
If it's by design, derive from box, implement the missing member(s) and use the derived class.
~ Answered on 2014-05-23 10:40:29