Solved

C++ : Casting from Template to a Base Class pointer... How?

Posted on 2013-05-23
3
598 Views
Last Modified: 2013-05-24
Here is a way I set up my design

class Master is a "interface".....

class Master{

      ~Master(){}

      virtual void setSomeThing(int aValue) = 0;
};

Class Slave is a template derived from Master.......

template <class PositionType, int Positionize>
class Slave : public Master
{
   Slave (std::string name, bool someValue)
   {
   }

   /* Overrides....*/
   void setSomeThing(int aValue) {/** Do sometthing here **/}
}

Note : PositionType is designed to take any enum type.

So in a main() I do the following...

main()
{

 Master* aMaster = new Slave <SomeType, someSize>("aName" ,false);
                                          /** SomeType is a enum type **/
 /** The above instantiation compiles and work good...**/
 
 //And then  I want the above object back to a Salve pointer....
 //So I try this,...
 
 Slave <SomeType, someSize>* convertback = (Slave <SomeType, someSize>) aMaster;
//Cannot do this. error.

}

So my question is.. how to cast the Master pointer (which is pointing to a Slave object) back to a Slave pointer?
0
Comment
Question by:prain
[X]
Welcome to Experts Exchange

Add your voice to the tech community where 5M+ people just like you are talking about what matters.

  • Help others & share knowledge
  • Earn cash & points
  • Learn & ask questions
3 Comments
 
LVL 37

Accepted Solution

by:
TommySzalapski earned 200 total points
ID: 39192515
Looks like you are just missing a *

Slave <SomeType, someSize>* convertback = (Slave <SomeType, someSize>*) aMaster
0
 

Author Closing Comment

by:prain
ID: 39192551
Oh! shoot. How come I did not see that. Thank you!
0
 
LVL 29

Expert Comment

by:pepr
ID: 39193582
Beware of the explicit cast that you are using. It came from C and using it, you give up some compile-time error detection. You should prefer

    static_cast <new_type> (expression)

or
   
    reinterpret_cast <new_type> (expression)
0

Featured Post

Free Tool: SSL Checker

Scans your site and returns information about your SSL implementation and certificate. Helpful for debugging and validating your SSL configuration.

One of a set of tools we are providing to everyone as a way of saying thank you for being a part of the community.

Question has a verified solution.

If you are experiencing a similar issue, please ask a related question

Many modern programming languages support the concept of a property -- a class member that combines characteristics of both a data member and a method.  These are sometimes called "smart fields" because you can add logic that is applied automaticall…
Whether you’re a college noob or a soon-to-be pro, these tips are sure to help you in your journey to becoming a programming ninja and stand out from the crowd.
This video teaches viewers about errors in exception handling.
Viewers will learn how to properly install Eclipse with the necessary JDK, and will take a look at an introductory Java program. Download Eclipse installation zip file: Extract files from zip file: Download and install JDK 8: Open Eclipse and …

739 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question