sharkdp · September 12, 2017 18:05
diff --git a/constants.h b/constants.h
 #pragma once

 extern double pi;
diff --git a/initialize.cpp b/initialize.cpp
 #include "constants.h"
 #include "initialize.h"

 double pi;

 void initializeConstants() {
    pi = 3.0;
 }
diff --git a/initialize.h b/initialize.h
 #pragma once

 #include "constants.h"

 void initializeConstants();
diff --git a/main.cpp b/main.cpp
 #include <iostream>

 #include "constants.h"
 #include "initialize.h"

 int main(int, char**) {
    initializeConstants();
    std::cout << pi << std::endl;
 }