error LNK2005, already defined?

c++

Solution

Why this error?

You broke the one definition rule and hence the linking error.

Suggested Solutions:

If you need the same named variable in the two cpp files then You need to use Nameless namespace(Anonymous Namespace) to avoid the error.

namespace 
{
    int k;
}

If you need to share the same variable across multiple files then you need to use `extern`.

A.h

extern int k;

A.cpp

#include "A.h"
int k = 0;

B.cpp

#include "A.h"

//Use `k` anywhere in the file 

Problem

I have 2 files, A.cpp and B.cpp, in a Win32 console application. Both 2 files contain only the following 2 lines of code: ``` #include "stdafx.h" int k; ``` When compiling it produces the error ``` Error 1 error LNK2005: "int k" (?a@@3HA) already defined in A.obj ``` I don't understand what is happening. Can someone please explain this to me?

Original source