What is wrong with my code organization?

First off, let me introduce you to the method of code organization I've been using. I'll have one main .cpp file where the basic functionality of the entire program can be understood. High-level functions called by the main .cpp file are placed in a .h file. Low-level functions called by the high-level functions are placed in other .h files and so on.

No compiler problems until I get to the issue of struct/object recognition among different .h files.

I've encountered problems with global structs being recognized in some compiled .h files, but not in others.

for example:

Code:

---

#ifndef low_level1
#define low_level1

struct my_struct
{
  int x;
  int y;
} its_mine;

#endif

---

Now, if I have several low-level .h files that use its_mine, and I #include "low_level1" in all of these other .h files, eventually I end up with compiler errors like:

Code:

---

error C2065: 'its_mine' : undeclared identifier

---

when some of the .h files are being compiled. Now I know what the error message means, it just means that the declaration of its_mine isn't found for some of the .h files even though I used #include "low_level1.h". This doesn't make sense to me why.

I temporarily fixed this by making all my globally used structs into objects and placing them all in an objects.h.

Now I have

Code:

---

#ifndef objects
#define objects
class my_class
{
public:
    int x;
    int y;
};
my_class its_mine;

#endif

---

I used #include "objects.h" in all of the .h files that used these objects and this worked for long enough that I thought that this was a solution to my woes. However, as my project grew I ended up with the same problem.

This isn't a method of code organization I learned from someone, it's just one I've used to serve my needs but I don't understand why compilers (I'm using VS2008) don't like it.

So my question is what is wrong with my code organization (besides the obvious answer everything)?

In case this isn't a question that can be answered without an exact example (some people make it sound like no question is) here are some snippets (I really hope no one thinks it's necessary to ask for all 10+ files and 5000+ lines of code...)

Code:

---


#ifndef objects
#define objects

class Squares{

int member;

};

#define SquaresY 13
#define SquaresX 6
Squares Square[SquaresY][SquaresX];

#endif

---

Code:

---


#ifndef image
#define image

#include "objects.h"
#include "low_level1.h"
#include "low_level2"

void myfunction()
{
  if((Square[0][0].member != 0)
  {
  ;
  }
}
#endif

---

sample error:
c:\visual studio\....\image.h(33) : error C2065: 'Square': undeclared identifier

wheras Square is recognized as declared in several other .h files:
low_level1.h,
low_level2.h, etc.

and:

Code:

---

#ifndef low_level1
#define low_level1

#include "objects.h"
#include "image.h"
#include "low_level2.h"

// Compiler recognizes Square
// Code that uses Square....

#endif

---

Code:

---

#ifndef low_level2
#define low_level2

#include "objects.h"
#include "image.h"
#include "low_level1.h"

// Compiler recognizes Square
// Code that uses Square....

#endif

---

Quote:

---

Originally Posted by notinasia

for example:

Code:

---

#ifndef low_level1
#define low_level1

struct my_struct
{
  int x;
  int y;
} its_mine;

#endif

---

---

Get rid of the "its_mine".

Code:

---

#ifndef low_level1
#define low_level1

struct my_struct
{
  int x;
  int y;
};

#endif

---

Once you do that, then work from there. Very rarely, if ever do C++ programmers create structs (and classes) with a trailing name. All that's needed is the struct or class definition.

If you now need to create a variable of type my_struct, then you do that in your implementation (.cpp) files, not in the header:

Code:

---

#include "low_level1.h"

int main()
{
  my_struct its_mine; 
//..
}

---

Also, if you really want to organize your code, get rid of the global variables. The issue you have has nothing to do with Visual C++ -- you have global variables declared in a header file, and you're including this header in multiple source files. What ends up happening is that the linker will see x number of global variables with the same name, and you can't have that (the linker will complain about multiple definitions of the same global variable).

Either get rid of the usage of global variables, or learn what the extern keyword does with respect to declaration of global variables.

Regards,

Paul McKenzie

Paul,

I tried

Code:

---

extern Squares Square[SQUARESY][SQUARESX]

---

In the function that uses Square[][] in image.h.

I then get

Code:

---

error C2146: syntax error : missing ';' before identifier 'Square'

---

However when I do the same thing in the function that uses Square[][] in lowlevel1.h, for example, I get no compiler errors.

I don't understand because there's no consistency. All of my global objects, and object definitions are recognized in all the other .h files except for in "image.h". I had a similar problem when I was using global structs. Everything compiled fine until my project got larger and then I started having similar compiler issues with the global structs. There were no syntax errors or anything, the global stuff just stopped being recognized in some files after the project got large enough...

I see that I did this incorrectly, I'll see if I can make this work with a .cpp and externs.....

I have 2 .cpp files now. Objects.cpp is for defining extern global objects declared in Objects.h this didn't cause any more compiler errors, and I can see how this is good for organization, but the globabl objects are still not recognized in image.h,

I have 10 .h files and 2 .cpp files, and 100+ compiler errors resulting from failure to recognize these global objects...... Like I said, one minute it was compiling fine then as the project got larger it just stopped recognizing them in some files but not others

errors are all of this form:

Code:

---

error C2065: 'Square' undeclared identifier
error C2228: left of '.member' must have class/struct/union

---

etc. etc.

and this is how I handled global definition/declartion:

objects.h

Code:

---

#ifndef objects
#define objects

/// includes

class Squares{

public:
          ////// members
};

//////////// #defines
extern Squares Square[SQUARESY][SQUARESX];

---

objects.cpp

Code:

---

#include "objects.h"

Squares Square[SQUARESY][SQUARESX];

---

#includes are not written that way. It should be

Code:

---

#include "objects.h"

---

Didn't your compiler tell you that?

Edit: When you get compiler errors always resolve the first one first. In many cases the ones that follow are because of the first one.

Quote:

---

Originally Posted by S_M_A

#includes are not written that way. It should be

Code:

---

#include "objects.h"

---

Didn't your compiler tell you that?

---

That is not copied and pasted from my project. The syntax in my project is correct.

Instead of focusing on quoting focus on cutting & pasting the exact code when posting. ;)

In post 6 you have posted a line that isn't terminated. Is that line copied or is it just a typo as well?

Quote:

---

Originally Posted by notinasia

and this is how I handled global definition/declartion:

---

You're all over the place here.

First, are you doing this off the top of your head, or are you following guidelines set by experienced C++ programmers? If it's the former and not the latter, then you're going to create a mess.

Second, it is preferable that you write applications with little, if any use of global variables.

Third, if you are going to use globals, start with the simplest of examples to learn how to use extern properly. One and only one source module must have the declaration without the extern keyword. All other modules must declare the global variable as extern.

Also, the issue is not whether the code will compile -- the issue is whether the code will link. That is where improper use of extern will cause errors, at the link stage, not the compile stage.

Code:

---

#include <iostream>

int x;
void foo();

int main()
{
    foo();
    std::cout << x;
}

---

Code:

---

extern int x;
void foo()
{
    x = 10;
}

---

Compile and link these two modules. You will see that there are no linker errors, and the code behaves as expected.

Also, if you have a lot of globals (again, not recommended), then the trick is to do this:

Code:

---

#ifndef MYHEADER_H
#define MYHEADER_H

#ifdef MAIN_MODULE
  #define EXTERN
#else
  #define EXTERN extern
#endif

EXTERN int x;
EXTERN int y;
EXTERN int z;

#endif

---

Then when you #include "Myheader.h", the file where you do not want extern to be used, just #define MAIN_MODULE at the top of the file:

Code:

---

#define MAIN_MODULE
#include "MyHeader.h"

int main()
{
}

---

And all other modules, you don't define MAIN_MODULE. I leave it to you to figure out why this works.

Regards,

Paul McKenzie

Unrelated to your problem, but will certainly add to confusion, why are you naming your class "Squares" (plural) and your array "Square" (singular)? That's the kind of thing that will drive you nuts later.

Paul,

Quote:

---

Originally Posted by Paul McKenzie

You're all over the place here.

First, are you doing this off the top of your head, or are you following guidelines set by experienced C++ programmers? If it's the former and not the latter, then you're going to create a mess.

---

I followed a stackoverflow guide: http://stackoverflow.com/questions/1...variables-in-c . I removed the extern declaration in "objects.h" if that is what you were concerned about.

Quote:

---

Originally Posted by Paul McKenzie

Also, the issue is not whether the code will compile -- the issue is whether the code will link. That is where improper use of extern will cause errors, at the link stage, not the compile stage.

---

I figured as much on this part though the errors follow after

Output:

Code:

---

Compiling...

---

I will try again with the format you gave me

I now have 1 .cpp and 10 .h's. This is a windows app if that makes a difference for any reason. I'm defining my globals in my main.cpp

main.cpp:

Code:

---

#define MAIN_MODULE

#include <windows.h>
#include "window_properties.h"
#include "resources.h"
#include "swordfight.h"
#include "play.h"
#include "objects.h"


handles_o handles;
Keys Key[NUM_KEYS] = {0,1,2,3,4};
Pieces Piece[2];
state_o state(0,0,0,0,1,0);
app_o app;
settings_o settings;

#define SquaresY 13
#define SquaresX 6

Squares Square[SquaresY][SquaresX];                // Array of the Game Squares
vector<Squares> Surface;
Squares Actual[2];
Squares Previous[2];
Squares Desired[2];

Squares Next[2];
Squares TopSquares;

Plans Plan[2];

Links_o Links;

/////// Code follows ////////////

---

In my objects.h I declare the globals:

Code:

---

#ifndef objects
#define objects

#ifdef MAIN_MODULE
        #define EXTERN
#else
        #define EXTERN extern
#endif

//#include<vector>
#include  "swordfight.h"
#include "object_functions.h"
#include <windows.h>
#include "resources.h"
#include <vector>
#include "image.h"


class handles_o
{
    HWND hwnd; // Process handle
    HIMAGELIST imagelist; // Imagelist handle
};
EXTERN handles_o handles;

class settings_o
{
        settings_o() {executable =DE1; pixels_x = DE2; pixels_y = DE3; colors = DE4;}
    string executable;
    int pixels_x;
    int pixels_y;
    char colors;
};
EXTERN settings_o settings;


#define P_THIS 0
#define P_NEXT 1
class Pieces
{
public:
        char bottom;
        char top;
};

EXTERN Pieces Piece[2];


#define CW 0
#define CCW 1

class state_o
{
public:
        void SetPlay(char p){ play = p;}
        bool GetPlay(){ return play==1;}
        void toggle_play() {play = !play & detect;}
        state_o(char p, char d, char v, char dt, char f, char w)
        {
                play = p; detect = d; valid = v; detectsf = dt; first = f; win = w; fail = 0;
        }
    char play;
    char detect;
    char valid;
    char detectsf;
        char first;       
        char win;
        char fail;
};


EXTERN state_o state;

class app_o
{
public:
    unsigned int x;
    unsigned int y;
    HWND hwnd;
        DWORD pid;
        HDC dc;
        RECT play_rect;        // play area
        RECT next_rect;        // next piece area
        RECT sb1_rect;        // score board 1 area
        RECT sb2_rect;        // score board 2
};

EXTERN app_o app;

///////////////////// Remaining declarations follow ///////////////////////////

---

I understand what the format you gave me does. I still have recognition problems in 2 of my .h files
image.h and configuration.h, both of which include objects.h.

I am doing everything the way you have suggested so it's odd that there are still problems. I will see if there's anything out of the ordinary in those two files (i.e. if there are any global variables defined in them or anything out of the ordinary).

Quote:

---

Originally Posted by notinasia

I now have 1 .cpp and 10 .h's. This is a windows app if that makes a difference for any reason. I'm defining my globals in my main.cpp

---

You're defeating the purpose of the EXTERN macro by redeclaring those same variables in main.cpp.

Code:

---

#include "objects.h"
handles_o handles;

---

The handles_o_ handles is already declared in objects.h. Why are you declaring it again? You do this with several variables in main().

Regards,

Paul McKenzie

I see. I combined the advice from you with the advice from stackoverflow..

While I'm fixing this.. will the following with initial values also work correctly?

Code:

---


EXTERN int i = 0;
EXTERN myclass its_mine(/* constructor arguments */);

---

Unfortunately I am still having the same errors. I will collapse all of my functions and post my project since nothing seems to be helping.

I attached screenshots of config.h, image.h and objects.h since copy paste still includes collapsed text.

error log:

Code:

---

------ Rebuild All started: Project: Swordfight, Configuration: Debug Win32 ------
Deleting intermediate and output files for project 'Swordfight', configuration 'Debug|Win32'
Compiling...
swordfight.cpp
c:\visual studio\swordfight\swordfight\swordfight\config.h(21) : error C2065: 'handles' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\config.h(21) : error C2228: left of '.hwnd' must have class/struct/union
        type is ''unknown-type''
c:\visual studio\swordfight\swordfight\swordfight\config.h(23) : error C2065: 'handles' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\config.h(23) : error C2228: left of '.hwnd' must have class/struct/union
        type is ''unknown-type''
c:\visual studio\swordfight\swordfight\swordfight\config.h(41) : error C2065: 'settings' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\config.h(41) : error C2228: left of '.executable' must have class/struct/union
        type is ''unknown-type''
c:\visual studio\swordfight\swordfight\swordfight\config.h(44) : error C2065: 'handles' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\config.h(44) : error C2228: left of '.hwnd' must have class/struct/union
        type is ''unknown-type''
c:\visual studio\swordfight\swordfight\swordfight\config.h(49) : error C2065: 'handles' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\config.h(49) : error C2228: left of '.hwnd' must have class/struct/union
        type is ''unknown-type''
c:\visual studio\swordfight\swordfight\swordfight\config.h(51) : error C2065: 'handles' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\config.h(51) : error C2228: left of '.hwnd' must have class/struct/union
        type is ''unknown-type''
c:\visual studio\swordfight\swordfight\swordfight\config.h(52) : error C2065: 'settings' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\config.h(52) : error C2228: left of '.pixels_x' must have class/struct/union
        type is ''unknown-type''
c:\visual studio\swordfight\swordfight\swordfight\config.h(58) : error C2065: 'handles' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\config.h(58) : error C2228: left of '.hwnd' must have class/struct/union
        type is ''unknown-type''
c:\visual studio\swordfight\swordfight\swordfight\config.h(60) : error C2065: 'handles' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\config.h(60) : error C2228: left of '.hwnd' must have class/struct/union
        type is ''unknown-type''
c:\visual studio\swordfight\swordfight\swordfight\config.h(61) : error C2065: 'settings' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\config.h(61) : error C2228: left of '.pixels_y' must have class/struct/union
        type is ''unknown-type''
c:\visual studio\swordfight\swordfight\swordfight\config.h(67) : error C2065: 'handles' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\config.h(67) : error C2228: left of '.hwnd' must have class/struct/union
        type is ''unknown-type''
c:\visual studio\swordfight\swordfight\swordfight\config.h(68) : error C2065: 'settings' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\config.h(68) : error C2228: left of '.colors' must have class/struct/union
        type is ''unknown-type''
c:\visual studio\swordfight\swordfight\swordfight\config.h(184) : warning C4800: 'int' : forcing value to bool 'true' or 'false' (performance warning)
c:\visual studio\swordfight\swordfight\swordfight\image.h(11) : error C2065: 'snip' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(11) : error C2228: left of '.height' must have class/struct/union
        type is ''unknown-type''
c:\visual studio\swordfight\swordfight\swordfight\image.h(12) : error C2065: 'snip' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(12) : error C2228: left of '.width' must have class/struct/union
        type is ''unknown-type''
c:\visual studio\swordfight\swordfight\swordfight\image.h(15) : error C2065: 'Previous' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(15) : error C2065: 'Actual' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(16) : error C2065: 'Previous' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(16) : error C2065: 'Actual' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(19) : error C2065: 'Square' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(19) : error C2065: 'Previous' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(19) : error C2228: left of '.me_y' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(19) : error C2065: 'Previous' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(19) : error C2228: left of '.me_y' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(21) : error C2228: left of '.top' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(21) : error C2059: syntax error : ')'
c:\visual studio\swordfight\swordfight\swordfight\image.h(27) : error C2065: 'y' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(27) : error C2065: 'y' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(27) : error C2065: 'y' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(29) : error C2065: 'x' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(29) : error C2065: 'x' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(29) : error C2065: 'x' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(32) : error C2065: 'Square' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(32) : error C2065: 'y' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(32) : error C2065: 'x' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(32) : error C2228: left of '.status' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(32) : error C2065: 'Square' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(32) : error C2065: 'y' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(32) : error C2065: 'x' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(32) : error C2228: left of '.neighbors' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(35) : error C2065: 'Square' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(35) : error C2065: 'y' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(35) : error C2065: 'x' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(35) : error C2228: left of '.status' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(35) : error C2065: 'Piece' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(35) : error C2065: 'THIS_TURN' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(35) : error C2228: left of '.bottom' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(38) : error C2065: 'Piece' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(38) : error C2065: 'THIS_TURN' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(38) : error C2228: left of '.bottom' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(38) : error C2065: 'Piece' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(38) : error C2065: 'THIS_TURN' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(38) : error C2228: left of '.top' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(43) : error C2065: 'Square' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(43) : error C2065: 'y' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(43) : error C2065: 'x' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(43) : error C2228: left of '.neighbor' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(43) : error C2065: 'Piece' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(43) : error C2065: 'THIS_TURN' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(43) : error C2228: left of '.bottom' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(47) : error C2065: 'Desired' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(47) : error C2228: left of '.me_y' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(47) : error C2065: 'Desired' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(47) : error C2228: left of '.me_y' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(53) : error C2065: 'Desired' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(53) : error C2228: left of '.me_y' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(53) : error C2065: 'Desired' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(53) : error C2228: left of '.me_y' must have class/struct/union
c:\visual studio\swordfight\swordfight\swordfight\image.h(55) : error C2065: 'Actual' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(55) : error C2065: 'Square' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(55) : error C2065: 'y' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(55) : error C2065: 'x' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(56) : error C2065: 'Actual' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(56) : error C2065: 'Square' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(56) : error C2065: 'y' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(56) : error C2065: 'x' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(57) : error C2143: syntax error : missing ';' before 'return'
c:\visual studio\swordfight\swordfight\swordfight\image.h(60) : error C2065: 'Actual' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(60) : error C2065: 'Square' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(60) : error C2065: 'y' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(60) : error C2065: 'x' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(61) : error C2065: 'Actual' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(61) : error C2065: 'Square' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(61) : error C2065: 'y' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(61) : error C2065: 'x' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(62) : error C2143: syntax error : missing ';' before 'return'
c:\visual studio\swordfight\swordfight\swordfight\image.h(66) : error C2065: 'Square' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(66) : error C2065: 'y' : undeclared identifier
c:\visual studio\swordfight\swordfight\swordfight\image.h(66) : fatal error C1003: error count exceeds 100; stopping compilation
Build log was saved at "file://c:\Visual Studio\Swordfight\Swordfight\Swordfight\Debug\BuildLog.htm"
Swordfight - 102 error(s), 1 warning(s)
========== Rebuild All: 0 succeeded, 1 failed, 0 skipped ==========

---

Quote:

---

Originally Posted by notinasia

I see. I combined the advice from you with the advice from stackoverflow..

While I'm fixing this.. will the following with initial values also work correctly?

Code:

---


EXTERN int i = 0;
EXTERN myclass its_mine(/* constructor arguments */);

---

---

Unfortunately no. That's why you should refrain from global variables when creating a C++ program.

Honestly, you would be better if you just created a class or struct with static data members. At the very least, that would be much easier to handle then "old C-style" global variables. You would see most, if not all of these problems disappear.

Regards,

Paul McKenzie

For example:

Code:

---

#ifndef objects
#define objects

//#include<vector>
#include  "swordfight.h"
#include "object_functions.h"
#include <windows.h>
#include "resources.h"
#include <vector>
#include "image.h"

class handles_o
{
    HWND hwnd; // Process handle
    HIMAGELIST imagelist; // Imagelist handle
};

class settings_o
{
        settings_o() {executable =DE1; pixels_x = DE2; pixels_y = DE3; colors = DE4;}
    string executable;
    int pixels_x;
    int pixels_y;
    char colors;
};

class Pieces
{
public:
        char bottom;
        char top;
};

class state_o
{
public:
        void SetPlay(char p){ play = p;}
        bool GetPlay(){ return play==1;}
        void toggle_play() {play = !play & detect;}
        state_o(char p, char d, char v, char dt, char f, char w)
        {
                play = p; detect = d; valid = v; detectsf = dt; first = f; win = w; fail = 0;
        }
    char play;
    char detect;
    char valid;
    char detectsf;
        char first;       
        char win;
        char fail;
};

class app_o
{
public:
    unsigned int x;
    unsigned int y;
    HWND hwnd;
        DWORD pid;
        HDC dc;
        RECT play_rect;        // play area
        RECT next_rect;        // next piece area
        RECT sb1_rect;        // score board 1 area
        RECT sb2_rect;        // score board 2
};

struct GlobalData
{
  static handles_o handles;
  static settings_o settings;
  static Pieces Piece[2];
  static state_o state;
  static app_o app;
};

#define P_THIS 0
#define P_NEXT 1

#define CW 0
#define CCW 1

#endif

---

Then in your main module is where you initialize your static members:

Code:

---

// main.cpp
#include "objects.h"
//...
 
handles_o GlobalData::handles;
settings_o GlobalData::settings;
Pieces GlobalData::Piece[2] = { whatever };
state_o GlobalData::state;
app_o GlobalData::app;


int main()
{
    //... whatever
}

---

Regards,

Paul McKenzie

So I'm not really making any progress on these linking problems, I'm considering just placing everything in 2-3 fat .h file so there's less room for linking problems...

The globaldata struct looks like another interesting idea, it would take a lot of time to add GlobalData. in front of everything at this point though.

Quote:

---

Originally Posted by notinasia

The globaldata struct looks like another interesting idea, it would take a lot of time to add GlobalData. in front of everything at this point though.

---

If I could get a dollar for every time I hear this, I would be a rich man.

I have dealt with code bases that are tens of thousands of lines of C++. When a global change needed to be made, it took me at most, a half-day, if that long to make the changes. What you do is this -- get rid of all of those global variables in your header file. Create the struct. Recompile your code. Fix the compiler errors. Done.

You will be surprised that this does not take a long time (not days, weeks, or months, maybe hours and sometimes minutes).

Also, the struct is one way to cut down on the number of globals, even 'C' programmers use this technique to bundle the globals in one place instead of having tons of global variables all over the code.



Regards,

Paul McKenzie