Why u shouldnt learn for a book...

[L0phtpDK]

OK... i recently got Windows 95 Programming For Dummies... (ill wait till u guys stop laughing) and i've have a problem with this code (im just pasting the whole damn thing):

#include <windows.h>

static int nRowSpacing;
static int nCharSpacing;

int WINAPI WinMain(
	HINSTANCE  hInstance,
	HINSTANCE  hPrevInstance,
	LPSTR	   pszCmdLine,
	int		   nCmdShow
   );

LRESULT CALLBACK WindowProc(
	HWND	hWnd,
	UINT	uMsgId,
	WPARAM  wParam,
	LPARAM  lParam
   );

void OutputLine(
	HDC  hDC,
	int  nRowNumber,
	char *pszDescription,
	int nValue
   );

int WINAPI WinMain(
	HINSTANCE  hInstance,
	HINSTANCE  hPrevInstance,
	LPSTR	   pszCmdLine,
	int		   nCmdShow
   )
{
	static char szAppName[] = "Prog2";
	HWND hWnd;
	MSG msg;
	WNDCLASS wndClass;

	wndClass.style		 = 0;
	wndClass.lpfnWndProc = WindowProc;
	wndClass.cbClsExtra	 = 0;
	wndClass.cbWndExtra  = 0;
	wndClass.hInstance	 = hInstance;
	wndClass.hIcon		 = LoadIcon(NULL,IDI_APPLICATION);
	wndClass.hCursor	 = LoadCursor(NULL, IDC_ARROW);
	wndClass.hbrBackground = GetStockObject(WHITE_BRUSH); 	//<--Right HERE 
	wndClass.lpszMenuName  = NULL;
	wndClass.lpszClassName = szAppName;
	if (RegisterClass(&wndClass) == 0)
	{
		return 0;
	}

	hWnd = CreateWindow(
			 szAppName,
			 szAppName,
			 WS_OVERLAPPEDWINDOW,
			 CW_USEDEFAULT,
			 CW_USEDEFAULT,
			 CW_USEDEFAULT,
			 CW_USEDEFAULT,
			 NULL,
			 NULL,
			 hInstance,
			 NULL);
	if (hWnd == 0)
	{
		return 0;
	}
	ShowWindow(hWnd, nCmdShow);
	UpdateWindow(hWnd);

	while (GetMessage(&msg, NULL, 0, 0))
	{
		TranslateMessage(&msg);
		DispatchMessage(&msg);
	}
	return msg.wParam;
}

LRESULT CALLBACK WindowProc(
	HWND	hWnd,
	UINT	uMsgId,
	WPARAM  wParam,
	LPARAM  lParam
   )
{
	HDC hDC;

	switch (uMsgId)
	{
	case WM_CREATE:
			hDC = GetDC(hWnd);

			TEXTMETRIC textMetrics;
			GetTextMetrics(hDC, &textMetrics);
			nRowSpacing = textMetrics.tmHeight + textMetrics.tmExternalLeading;
			nCharSpacing = textMetrics.tmAveCharWidth;

			ReleaseDC(hWnd, hDC);
			return 0;

	case WM_PAINT:
			PAINTSTRUCT paintStruct;
			hDC = BeginPaint(hWnd, &paintStruct);

			OutputLine(hDC, 1,
				       "Avg Char Spactin = ",
					   nCharSpacing);
			OutputLine(hDC, 2,
					   "Row spacing = ",
					   nRowSpacing);


			RECT rectWindow;
			GetWindowRect(hWnd, &rectWindow);
			OutputLine(hDC, 4,
					   "Window x location = ",
					   rectWindow.left);
			OutputLine(hDC, 5,
					   "Window y location = ",
					   rectWindow.top);

			OutputLine(hDC, 7,
					   "Window x dimension = ",
					   rectWindow.right - rectWindow.left);
			OutputLine(hDC, 8,
					   "Window y dimension = ",
					   rectWindow.bottom - rectWindow.top);

			EndPaint(hWnd, &paintStruct);
			return 0;

	case WM_DESTROY:
			PostQuitMessage(0);
			return 0;

	default:
		return DefWindowProc(hWnd,uMsgId,wParam,lParam);
	}
}

void OutputLine(
	HDC  hDC,
	int  nRowNumber,
	char *pszDescription,
	int nValue
   )
{
	int nCol1Offset = 20;
	int nCol2Offset = nCol1Offset + 25 * nCharSpacing;
	int nRowOffset = nRowNumber * nRowSpacing;

	SetTextAlign(hDC, TA_LEFT | TA_TOP);
	TextOut(hDC,
			nCol1Offset,
		    nRowOffset,
			pszDescription,
			lstrlen(pszDescription));

	SetTextAlign(hDC, TA_RIGHT | TA_TOP);
	char szBuffer[16];
	wsprintf(szBuffer, "%d", nValue);
	TextOut(hDC,
			nCol2Offset,
		    nRowOffset,
			szBuffer,
			lstrlen(szBuffer));
}

And the error is this:

error C2440: '=' : cannot convert from 'void *' to 'struct HBRUSH__ *'
        Conversion from 'void*' to pointer to non-'void' requires an explicit cast

What is the fastest and easiest way to fix this sort of a problem. Also, word of the wise, don't try to learn from book!

[L0phtpDK]

the debugger points to:

	wndClass.hbrBackground = GetStockObject(WHITE_BRUSH); 	//<--Right HERE

Sorry that the code is a tad disorganized... i dunno why it messed up while i was copying and pasting

[hmm]

Hello L0phtpDK

Try casting

Example:

wndClass.hbrBackground = (WNDCLASS) GetStockObject(WHITE_BRUSH);

I had the same problem 2 hrs ago..it may work

HTH

hmm

[L0phtpDK]

did work.. i got this error now:

Cpp1.cpp
C:\Windows\Desktop\programin\prog2\Cpp1.cpp(46) : error C2440: 'type cast' : cannot convert from 'void *' to 'struct tagWNDCLASSA'
        No constructor could take the source type, or constructor overload resolution was ambiguous
Error executing cl.exe.

and just to make sure.. my code is now:

	wndClass.style		 = 0;
	wndClass.lpfnWndProc             = WindowProc;
	wndClass.cbClsExtra	 = 0;
	wndClass.cbWndExtra              = 0;
	wndClass.hInstance	 = hInstance;
	wndClass.hIcon		 = LoadIcon(NULL,IDI_APPLICATION);
	wndClass.hCursor	                 = LoadCursor(NULL, IDC_ARROW);
    wndClass.hbrBackground = (WNDCLASS) GetStockObject(WHITE_BRUSH);  	//<--Right HERE 
	wndClass.lpszMenuName  = NULL;
	wndClass.lpszClassName = szAppName;

[L0phtpDK]

ok... after reading the last msg that u mentioned before... i did the following:

wndClass.hbrBackground = (HBRUSH) GetStockObject(WHITE_BRUSH);

it compiled... but it wont let me build it... i get this error when i build it:

Linking...
LIBCD.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
Debug/Cpp1.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

I take it i was wrong when i did that....

[hmm]

Hi L0phtpDK

Change the line to read:

wndClass.hbrBackground = (HBRUSH) GetStockObject(BLACK_BRUSH); //<--Right HERE

It compiled for me and ran



HTH

hmm

[L0phtpDK]

it compiles... but i cant Build it.
it says i still have a linking error.

[hmm]

Hi L0phtpDK


Extract from a FAQ:

I get following errors when compiling the Win32 demos : 'libcd.lib(crt0.obj) : error LNK2001: unresolved external symbol _main' 'Debug/main.exe : fatal error LNK1120: 1 unresolved externals'.

This error occurs in VC when you're trying to compile a Win32 project as a console application. The compiler then searches for the function 'main', which causes the error. To fix this, copy your files into a directory, open a Win32 project and add the files to the project. Everything should compile fine. If you're compiling from the command prompt you should add '-mwindows'.


HTH

hmm

[CornedBee]

easier way than copiying and pasting:
in the linker options in project settings, change
/subsystem:console
to
/subsystem:windows

It should search for WinMain then.