Question

I have already seen a post about the error but This is some what different. So please donot close this. I have an Interface class and I have a class that inherits the interface class and overides the methods in Interface class. The code looks likes this

//interface file
//Interface.h
class A
{
    virtual method1();
};


//b.h 
#include "Interface.h"
class B : public A
{
     //declaration   
}

//b.cxx
#include b.h
B::method1()
{
    //definition
}

I am exporting all these classes in a dll. And I am using methods and classes in the dll from an exe. This exe agains contains somes classes. These classes again inherit the same interface file and also uses method1(). So to use method1() I am including b.h in my file. If order of my include statements are Interface.h and b.h, then I am getting Compiler error for exe. Telling “base class not defined“. But if I reorder the Include statement there is no compilation error. Can any one suggest me what could be basic reason for this problem.

Answer 1

There are actually two errors in your example code: First you do not declare the method without a return type, which is an error. The second is that you, at least in the snippet above, do not declare method1 in the class definition of B:

class B : public A
{
    virtual void method1();
};