Question

Coming from a C# background from a night course at a local college, I’ve sort of started my way in C++. Having a lot pain getting used to the syntax. I’m also still very green when it comes to coding techniques.

From my WinMain function, I want to be able to access a variable which is using an enum I declared in another class.

(inside core.h)
class Core
{
    public:
    enum GAME_MODE
    {
        INIT,
        MENUS,
        GAMEPLAY
    };
    GAME_MODE gameMode;

    Core();
    ~Core();
    ...OtherFunctions();
};

(inside main.cpp)
Core core;
int WINAPI WinMain(...)
{
    ... startup code here...

    core.gameMode = Core.GAME_MODE.INIT;

    ...etc...
}

Basically I want to set that gameMode to the enum value of Init or something like that from my WinMain function. I want to also be able to read it from other areas.

I get the error…

expected primary-expression before '.' token

If I try to use core.gameMode = Core::GAME_MODE.INIT;, then I get the same error.

I’m not fussed about best practices, as I’m just trying to get the basic understanding of passing around variables in C++ between files. I’ll be making sure variables are protected and neatly tucked away later on once I am use to the flexibility of the syntax.

If I remember correctly, C# allowed me to use Enums from other classes, and all I had to do was something like Core.ENUMNAME.ENUMVALUE.

I hope what I’m wanting to do is clear :\ As I have no idea what a lot of the correct terminology is.

Answer 1

Use

core.gameMode = Core::INIT;

The individual values of an enumeration are scoped not within that enumeration but at the same level as the enumeration itself. This is something that most other languages (including C#) do differently, and C++0x will allow both variants so that there,

core.gameMode = Core::GAME_MODE::INIT;

will also be legal.

In addition, the strongly typed enums that will be added in C++0x (enum class) will put the enum values only within the scope of the enum (i.e. as in C#); this solves the problem you noted in your comment that for “normal” enums, the identifiers for enum values need to be unique across all enums defined in the same scope.