C++: undefined reference to.....?

I have two objects A, and B. In A i have a function:


A::addB(B *b)


{


int bresult = b-%26gt;getResult();


..............


}





when compiled with g++ i get:


undefined reference to 'B::getResult()'


I didn't forget to include the header file for B

C++: undefined reference to.....?
When you get an "undefined reference" error, your problem won't be solved with #includes (assuming you are trying to link to a method defined in a .cpp, and all your #includes reference only .h files). The reason this is happening is that the object file in which B::getResult() is defined is not being found by the linker. So there is probably a file B.o that will have to be referenced in your linking line. Here's an abstraction of the g++ calls:





g++ -c A.cpp B.cpp


g++ -o myprogram A.o B.o
Reply:Include header for class B before using in class A.


Alternatively, this method will work.





// Header file


class B;


class A


{


public:


void addB(B *);


...


};


class B


{


public:


int getResult();


...


}





// Source file


void A::addB(B *b)


{


int bresult = b-%26gt;getResult();


...


}


That should fix your problem.
Reply:What does your compile command look like? You might have to make sure to G++ a.cpp b.cpp





Or something like that.





There are other causes: Is getResult() public on B?