Question

I wanna create a global object in cpp program, how do I do that?
Is this right?
in “global_obj.h”

#include "class.h"
Class obj;

in “main.cpp”

extern Class obj;

Answer 1

We declare our globals as extern in a header file, in your case: global_obj.h, and the actual global variable in a source file: global_obj.cpp. In separate source files we #include "global_obj.h" to have access to them.

It should look like this:

global_obj.cpp

Class obj;

global_obj.h

extern Class obj;

main.cpp

#include "global_obj.h"