Problems with modules

// http://www.cprogramming.com/tutorial/gamedesign.html

I have read article about modules (game design) && I'm having some problems with implementation...

When I try to compile my code, it works. I run the program && get unhandled exception error... Program exits and places my pointer on the following line :

Code:

if ( (GameMod = GameMod->execute_module()) != OldMod )

Can someone help me with this? Code is too big to put here. If anyone has some time, I can send complete source code and VS.NET 2003 project file in .zip archive.


And... can you give me advice where should I use modules. Do I need to make module for everything or...?

For example, I have class Unit, class Vehicle... Should I also make modules for them?

Still confused with these modules...

You should read through the discussion thread, jverkoey made some posts that might clear up your confusion a bit.

And I can't really say what your problem is without seeing some code...

Here is the source : http://www.myfilestash.com/userfiles...se_00000_1.zip

[NOTE] :
Some files have been excluded from the project.

I think that problem is in those 'extern Module* x...' ,
tried many things but can't get thing to work.

I think you should put the extern's in module.h, declare them without extern in the corresponding .cpp file. ie:

Code:

//module.h
class Module
{
//...
}

extern Module* GameMod;
//...

Code:

//GameModule.cpp
Module* GameMod;

//...

Then you need to allocate those with new (probably in some initialization function (in GameLoop.cpp i guess):

Code:

Module* this_file_gamemod = GameMod; //don't confuse the two

void Startup()
{
GameMod = new GameModule();
this_file_gamemod = GameMod;
}

void GameLoop()
{

Module* oldmod = this_file_gamemod;
//...

}

void ShutDown()
{
  delete GameMod;
}

Module && GameModule are abstract classes, so I can't use new on them.

Well its not going to work the way you have it here:

Code:

Module*	GameMod = NULL;
	Module*	LastMod = NULL;

	//-----------------------------------------------------------------
	//	GameLoop()
	//-----------------------------------------------------------------
	void GameLoop()
	{

		Module* OldMod = GameMod;

		if ((GameMod = GameMod->execute_module()) != LastMod)
		{
			LastMod = OldMod;

		}
	}

If GameMod is null then you can't call its member functions...Unless I'm missing something?

I don't think GameModule should be an abstract class, in any case...

I'm still new to abstract classes. How can I make class not to be abstract ?
Make pure virtual ( =0) functions virtual ?

A class is abstract if it has a pure virtual function IIRC (that is, a virtual function with =0 at the end of the declaration)

So you shouldn't have any virtuals in GameModule, just normal function declarations and definitions

Thanks for help.
I started rewriting externs... need to get rid of those unresolved externals.