Variable already defined in .obj; What is going on here?

Question

head.h

#pragma once

namespace foo
{
    int bar;

    int funct1();
}

head.cpp

#include \"head.h\"

int foo::funct1()
{
         


        

Answer 1

This foo namespace-level bar declaration:

namespace foo
{
    int bar;
}

is actually a definition.

To make it a declaration, mark the bar as extern in head.h:

namespace foo
{
    extern int bar;
}

Then define it in head.cpp:

int foo::bar = 0;