I have a design related question.
Say I have 2 classes, class A and class B
I havea third class classMain, where I want to use wither classA or classB at runtime based on some parameters.
I am planning to create a void pointer (as below) in the classMain and then point it either classA or classB object at runtime.
Are there any other alternatives to this approach?Code:classMain { ... .... void * classptr; }
Thanks in advance.
er.. Is that actually possible(pointing a void* to a class) in C++ ?I am planning to create a void pointer (as below) in the classMain and then point it either classA or classB object at runtime.
You could point it towards objects of those classes.
If the objects are small in size and you do not have memory constrains, I think it'd be simpler and better to put each of the objects in the class and use them as necessary.
Last edited by manasij7479; 08-06-2011 at 09:12 AM.
thanks for the response.
yes, it will point to the object of the class.
i should have named it as "void * objptr;"
Yes, having the objects is one solution; or better have the pointers and allocated mem only if neeed.
Code:classMain { ... .... class A* objAptr; class B* objBptr; }
You'd better omit the 'class' words in the declarations of the pointers..
I wonder if inheritance and polymorphism would be appropriate here. What are these parameters, and what do classA and classB have in common?Originally Posted by nappaji
It is legal for a void* to point to an object of non-POD class type.
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I thought(at first) he wanted to point the void* to the class instead of the object and then use it to make objects of the required type.It is legal for a void* to point to an object of non-POD class type.
Last edited by manasij7479; 08-06-2011 at 11:51 AM.
The classes dont have much in common, hence did not consider inheritance. Moreover only one of them will be used at any instance.
void * is to point to objects, not class.
Then why do you want classMain to select one of them at run time? It sounds like you have two separate paths of control, and this classMain is either redundant, or perhaps should be two different classes.
That has no bearing on whether inheritance and polymorphism is appropriate.
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