// Color.h
class Color {
protected:
    int id;
    Color(int id) : id(id) {}
    void operator&(); //undefined
public:
    Color(const Color& r) : id(r.id) {}
    Color& operator=(const Color& r) {id=r.id; return *this;}
    bool operator==(const Color& r) const {return id==r.id;}
    bool operator!=(const Color& r) const {return id!=r.id;}
    operator int() const {return id;} //so you can still switch on it

    static Color Blue;
    static Color Red;
};

// Color.cpp
#include "Color.h"

Color Color::Blue(0);
Color Color::Red(1);

// main.cpp
#include "Test.h"
using namespace std;

const Color mainColors[] = {Color::Red, Color::Red }; // values should be [1, 1]

int main()
{
    cout << "Main file-scoped colors: " << mainColors[0] << ", " << mainColors[1] << endl; // prints [1, 1]
    Test();
    return 0;
}

// Test.h
#include "Color.h"
void Test();

// Test.cpp
#include "Test.h"
const Color fooColors[] = {Color::Red, Color::Red}; // values should be [1, 1]

void Test()
{
    cout << "Test file-scoped colors: " << fooColors[0] << ", " << fooColors[1] << endl; // prints [0, 0]
}

static Color Blue();
static Color Red();

Color Color::Blue() {return Color(0);}
Color Color::Red() {return Color(1);}

const Color mainColors[] = {Color::Blue(), Color::Red() };

const Color fooColors[] = {Color::Blue(), Color::Red()};