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

How is it being defined multiple times?

It is defined once in head.cpp and once in main.cpp. That is a total of two times. This violates the one definition rule, which states that there may only be one definition for every variable.

int bar;

This is a definition of a variable. You've included it into two translation units.

A variable can be declared without definition in an extern declaration:

extern int bar;

Replace the definition with such declaration, and put the definition into exactly one translation unit.