Classes and Win32 API, and another Question

Hello,
After programming in Win32 console c++, I feel most ready to start Win32 API. I got down making a blank window, some little text on the screen, but I'm aslo wondering if all C++ is available when using win32 API. Reason I ask is I'm wondering if Classes work as well. For example, the header has my class, and can I still make objects with it on the main source? Does it work like MFC?

Also, I'm trying to make an object's variable show up on a message box. For example,

MessageBox(NULL, PC.Age, "Message", MB_OK);

I get the following Errors:
error C2065: 'Player' : undeclared identifier
error C2146: syntax error : missing ';' before identifier 'PC'
error C2065: 'PC' : undeclared identifier
error C2228: left of '.Age' must have class/struct/union type
error C2228: left of '.Age' must have class/struct/union type


Where do I define objects? In the switch() cases? Any help is appreciated. Thanks.

>>I'm aslo wondering if all C++ is available when using win32 API<<

Yes, limited only by your compiler's capabilities.

>>Where do I define objects? In the switch() cases?<<

Without seeing more code (and use code tags please) it's almost impossible to answer. Still, taking a wild guess that the 'switch' you're referring to is a message handling switch statement within a window procedure then you can declare 'Player' with static scope at the start of the window procedure. For simplicity/testing you may wish to declare the object instance with global scope.

Code:

---

switch(Msg)
{
        case WM_MBUTTONDOWN:
                Player PC;
                PC.Age = 22;
        MessageBox(NULL, Player.Age, "Message", MB_OK);
        break;
}

---

There ya go. It says:
'Player' : illegal use of this type as an expression

Enclose the case statement in chicken lips:

Code:

---

case WM_MBUTTONDOWN:
  { //<--- one of these...
  Player PC;
  PC.Age = 22;
  MessageBox(NULL, Player.Age, "Message", MB_OK);
  break;
  } //<-- ... and another

---

Note that the scope of the declaration (Player PC) will be local to that case statement; if you want to access the object elsewhere then you'll have to declare the object instance with static or global scope as I previously mentioned.

Oh yeah, I remember the brackets purpose now. And yea, defining an object should be global, me thinks.

Thanks.

No matter what I do, it wont work. Here's the script..

Code:

---


#include <windows.h>


const char g_szClassName[] = "myClassWindow";
 


LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{

        PAINTSTRUCT PaintStruct;
        HDC hDC;


        switch(Msg)
        {
                case WM_MBUTTONDOWN:
                                                  { //<--- one of these...
                                                    Player PC;
                                                  PC.Age = 22;
                                                  MessageBox(NULL, Player.Age, "Message", MB_OK);
                                                  break;
                                                  } //<-- ... and another
                case WM_PAINT:  hDC = BeginPaint(hWnd, &PaintStruct);
                                            TextOut(hDC, 10, 10, "Hi", 2);
                                            EndPaint(hWnd, &PaintStruct);
                                            break;
               
                case WM_CLOSE:  DestroyWindow(hWnd);
                                            break;
               
                case WM_DESTROY: PostQuitMessage(0);
                                                break;
                default:        return DefWindowProc(hWnd, Msg, wParam, lParam);
        }
        return 0;
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
        WNDCLASSEX wc;
        HWND hWnd;
        MSG Msg;

        // Registering Class Window
        wc.cbClsExtra                        = 0;
        wc.cbSize                                = sizeof(WNDCLASSEX);
        wc.cbWndExtra                        = 0;
        wc.hbrBackground                = (HBRUSH) (COLOR_WINDOW+1);
        wc.hCursor                                = LoadCursor(NULL, IDC_ARROW);
        wc.hIcon                                = LoadIcon(NULL, IDI_APPLICATION);
        wc.hIconSm                                = LoadIcon(NULL, IDI_APPLICATION);
        wc.hInstance                        = hInstance;
        wc.lpfnWndProc                        = WndProc;
        wc.lpszClassName                = g_szClassName;
        wc.lpszMenuName                        = NULL;
        wc.style                                = 0;

        if (!RegisterClassEx(&wc))
        {
                MessageBox(NULL, "Registering Class Failed!", "Message", MB_ICONEXCLAMATION | MB_OK);
                return 0;
        }

        // Creating Window
        hWnd = CreateWindowEx(WS_EX_CLIENTEDGE, g_szClassName, "World of Dragons", WS_OVERLAPPEDWINDOW,
                CW_USEDEFAULT, CW_USEDEFAULT, 800, 600, NULL, NULL, hInstance, NULL);

        if (hWnd == NULL)
        {
                MessageBox(NULL, "Creating Window Failed!", "Message", MB_ICONEXCLAMATION | MB_OK);
                return 0;
        }

        // Misc, but not last...

        ShowWindow(hWnd, nCmdShow);
        UpdateWindow(hWnd);

        while (GetMessage(&Msg, NULL, 0, 0) > 0)
        {
                TranslateMessage(&Msg);
                DispatchMessage(&Msg);
        }

        return Msg.wParam;
}

---

Header:

Code:

---

#include <iostream>

class Player
{
public:
        unsigned short int Age;
};

---

And last, our bugs:

Code:

---

C:\Program Files\Microsoft Visual Studio\MyProjects\WIN32Pract2\Main.cpp(5) : error C2146: syntax error : missing ';' before identifier 'PC'
C:\Program Files\Microsoft Visual Studio\MyProjects\WIN32Pract2\Main.cpp(5) : error C2501: 'Player' : missing storage-class or type specifiers
C:\Program Files\Microsoft Visual Studio\MyProjects\WIN32Pract2\Main.cpp(5) : fatal error C1004: unexpected end of file found

---

Quote:

---

Originally Posted by philvaira

LRESULT CALLBACK WndProc(HWND hWnd, UINT Msg, WPARAM wParam, LPARAM lParam)
{

PAINTSTRUCT PaintStruct;
HDC hDC;


switch(Msg)
{
case WM_MBUTTONDOWN:
{ //<--- one of these...
Player PC;
PC.Age = 22;
MessageBox(NULL, Player.Age, "Message", MB_OK);
break;
} //<-- ... and another

---

Try this:

Code:

---

switch(Msg)
 case WM_MBUTTONDOWN:
  {
    Player PC;
    PC.Age = 22;
    MessageBox(NULL, PC.Age, "Message", MB_OK);
  }

  break;

---

You haven't #included the header file which contains the definition/declaration of Player. Alternatively, just add the contents of 'header' immediately after you #include <windows.h>.

Also, you can't pass numbers to the MessageBox function; you have to convert them the strings first. For example:

Code:

---

case WM_MBUTTONDOWN:
  {
  Player PC;
  PC.Age = 22;
  TCHAR chTxt[32];
  wsprintf(chTxt,TEXT("%d"),PC.Age);
  MessageBox(NULL, chTxt, "Message", MB_OK);
  break;
  }

---

edit: typos

Code:

---

error C2664: 'MessageBoxA' : cannot convert parameter 2 from 'unsigned short' to 'const char *'

---

My spider senses are telling me that MessageBox() only uses chars instead of integers. I tried the following, and it worked for char's.

Code:

---

switch (Msg)
{
        case WM_MBUTTONDOWN:
        {
        char Name[] = "Phil";
        MessageBox(NULL, Name, "Message", MB_OK);
                }

---

There we go.. thanks :)

>>error C2664: 'MessageBoxA' : cannot convert parameter 2 from 'unsigned short' to 'const char *'<<

Strange...

TCHAR is only typedef'd as unsigned short (ie. wchar_t) when UNICODE is defined (and as char when it isn't) which, if true, would mean that MessageBoxW would be called...

Still, glad that you have it working now. :)