[c++] - Help about class and error: C3861

Question

Can someone help me in this error?

in "cDef.h" :

#pragma once

class cDef 
{
public:

    static int STATE_LOGO;
    static int STATE_MENU;

    static int MESSAGE_ENTER;
    static int MESSAGE_UPDATE;
    static int MESSAGE_PAINT;
    static int MESSAGE_EXIT;
};

in "GameState.h":

#pragma once
#ifndef _GameState_
#define _GameState_
#include "cDef.h"

class MainGame;
class GameState;


class GameState
{
public:

    MainGame *mg;
    int GAME_STATE_DEF;

    virtual void MessengeEnter(int message) = 0;
    virtual void MessengeUpdate(int message,int keys) = 0;
    virtual void MessengePaint(int message,CDC *pDc) = 0;

void StateHandler(int message,CDC *pDc,int keys);

public:
    GameState(void);
public:
    ~GameState(void);
};
#endif

in "GameState.cpp":

#include "StdAfx.h"
#include "GameState.h"

GameState::GameState(void)
{
    GAME_STATE_DEF = -1;
}

GameState::~GameState(void)
{
}

void GameState::StateHandler(int message,CDC *pDc,int keys)
{
    if(message == cDef.MESSAGE_ENTER)
    {
        MessageEnter(message);
    }

    if(message == cDef.MESSAGE_UPDATE)
    {
        MessageUpdate(message,keys);
    }

    if(message == cDef.MESSAGE_PAINT)
    {
        MessagePaint(message,pDC);
    }
}

error:

warning C4832: token '.' is illegal after UDT 'cDef'
see declaration of 'cDef'
error C3861: 'MessageUpdate': identifier not found
error C3861: 'MessageEnter': identifier not found
error C3861: 'MessagePaint': identifier not found
...

Thanks in advance!

Answer 1

You access static variables by using the scope operator :: instead of the member access operator .

Example:

cDef::MESSAGE_ENTER

Also you should be initializing the members of cDef in your cpp file to some value. In this scenario an enum is probably better by the way.

Answer 2

Here's what I used to hammer into my students who had to learn C++ coming from Java and always were confused about when to use ::, ., and ->:

• A::B means A is either a class or a namespace name.
• A.B means A is either an object or a reference to an object.
• A->B means A is either a pointer or an object of a type that has operator-> overloaded (a.k.a. "smart pointer")

If you know these, you can also apply them backwards, so that if you have an A and a B, you know what to put in between.

(I think these rules would have to be extended for C++11, but I'm not sure. If you know, feel free to add this.)

Answer 3

This seems to be obvious once you see it - you declare the member function

virtual void MessengeEnter(int message) = 0;

but call

MessageEnter(message);

(notice the difference between Messenge and Message)