Why cant i put this in a header file?
error C2143: syntax error : missing ';' before '.'
error C4430: missing type specifier - int assumed.
error C2371: 'rect' : redefinition; different basic types
Code:RECT rect ; rect.left = 15 ; rect.top = 15 ; rect.right = 235 ; rect.bottom = 125 ;
Using Windows 10 with Code Blocks and MingW.
Put your assignments inside a function body.
If you dance barefoot on the broken glass of undefined behaviour, you've got to expect the occasional cut.
If at first you don't succeed, try writing your phone number on the exam paper.
Declarations and definitions can appear outside functions. Code cannot.
You should not define or declare variables in headers, either.
Originally Posted by Adak
Code:RECT rect = {15,15,235,125}; // rect.left = 15 ; // rect.top = 15 ; // rect.right = 235 ; // rect.bottom = 125 ;
Salem, Elysia, Bob, thank you.
Bob's version is working.
Using Windows 10 with Code Blocks and MingW.
Yes, it's called initialization. Initialization can be done outside functions, but assignments cannot.
Ive been trying to solve this all week, still i cant see the reason why.
If i put the variables in the .cpp file it works fine.
If i put the variables in the .h file, outside the function, it only draws the first rectangle.
If i put the variables in the .h file, inside the function, it doesnt draw anything at all.
Code:#include <windows.h> #include "variables.h" #define ID_TIMER 101 LRESULT CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM) ; int WINAPI WinMain (HINSTANCE hInstance, HINSTANCE hPrevInstance, PSTR szCmdLine, int iCmdShow) { static TCHAR szAppName[] = TEXT ("Invalidaterect") ; HWND hwnd ; MSG msg ; WNDCLASS wndclass ; wndclass.style = CS_HREDRAW | CS_VREDRAW ; wndclass.lpfnWndProc = WndProc ; wndclass.cbClsExtra = 0 ; wndclass.cbWndExtra = 0 ; wndclass.hInstance = hInstance ; wndclass.hIcon = LoadIcon (NULL, IDI_APPLICATION) ; wndclass.hCursor = LoadCursor (NULL, IDC_ARROW) ; wndclass.hbrBackground = (HBRUSH) GetStockObject (BLACK_BRUSH) ; wndclass.lpszMenuName = NULL ; wndclass.lpszClassName = szAppName ; if (!RegisterClass (&wndclass)) { return 0 ; } hwnd = CreateWindow (szAppName, // window class name TEXT ("The Hello Program"), // window caption WS_OVERLAPPEDWINDOW, // window style CW_USEDEFAULT, // initial x position CW_USEDEFAULT, // initial y position CW_USEDEFAULT, // initial x size CW_USEDEFAULT, // initial y size NULL, // parent window handle NULL, // window menu handle hInstance, // program instance handle NULL) ; // creation parameters ShowWindow (hwnd, iCmdShow) ; UpdateWindow (hwnd) ; while (GetMessage (&msg, NULL, 0, 0)) { TranslateMessage (&msg) ; DispatchMessage (&msg) ; } return msg.wParam ; } LRESULT CALLBACK WndProc (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { switch (message) { case WM_SIZE: cxClient = LOWORD (lParam) ; cyClient = HIWORD (lParam) ; return 0 ; case WM_CREATE: SetTimer (hwnd, ID_TIMER, 1000, NULL); break; case WM_TIMER : bFlipFlop = !bFlipFlop ; InvalidateRect (hwnd, &rect1, FALSE) ; InvalidateRect (hwnd, &rect2, FALSE) ; InvalidateRect (hwnd, &rect3, FALSE) ; InvalidateRect (hwnd, &rect4, FALSE) ; return 0 ; case WM_PAINT: hdc = BeginPaint(hwnd, &ps); paint(); EndPaint(hwnd, &ps); return 0 ; case WM_DESTROY: KillTimer (hwnd, ID_TIMER) ; PostQuitMessage (0) ; return 0 ; } return DefWindowProc (hwnd, message, wParam, lParam) ; }Code://variables.h static BOOL bFlipFlop = FALSE ; HDC hdc ; PAINTSTRUCT ps ; HBRUSH hBrush ; static int cxClient, cyClient ; //RECT rect1,rect2,rect3,rect4; RECT rect1 = {15,15,235,125} ; POINT arrow1 [7] = {{20, 50},{180, 50},{180, 20},{230, 70}, {180, 120},{180, 90},{20, 90}} ; RECT rect2 = {cxClient -235, 15, cxClient -15, 125} ; POINT arrow2 [7] = {{cxClient -230, 70},{cxClient -170, 20},{cxClient -170, 50},{cxClient -25, 50}, {cxClient -25, 90},{cxClient -170, 90},{cxClient -170, 120}} ; RECT rect3 = {15, cyClient -125, 235, cyClient -15} ; POINT arrow3 [7] = {{20, cyClient -90},{180, cyClient-90},{180, cyClient-120}, {230, cyClient-70},{180, cyClient-20}, {180, cyClient-50},{20, cyClient-50}} ; RECT rect4 = {cxClient -235, cyClient -125, cxClient -15, cyClient -15} ; POINT arrow4 [7] = {{cxClient -230, cyClient -70},{cxClient -170, cyClient -120}, {cxClient -170, cyClient -90}, {cxClient -25, cyClient -90}, {cxClient -25, cyClient -50}, {cxClient -170, cyClient -50}, {cxClient -170, cyClient -20}} ; void paint() { //rectangles hBrush = CreateSolidBrush (bFlipFlop ? RGB(255,0,0) : RGB(0,0,255)) ; FillRect (hdc, &rect1, hBrush) ; hBrush = CreateSolidBrush (bFlipFlop ? RGB(0,0,255) : RGB(255,0,0)) ; FillRect (hdc, &rect2, hBrush) ; hBrush = CreateSolidBrush (bFlipFlop ? RGB(0,0,255) : RGB(255,0,0)) ; FillRect (hdc, &rect3, hBrush) ; hBrush = CreateSolidBrush (bFlipFlop ? RGB(255,0,0) : RGB(0,0,255)) ; FillRect (hdc, &rect4, hBrush) ; //arrows hBrush = CreateSolidBrush (bFlipFlop ? RGB(0,0,255) : RGB(255,0,0)) ; SelectObject(hdc, hBrush); Polygon(hdc, arrow1, 7); hBrush = CreateSolidBrush (bFlipFlop ? RGB(255,0,0) : RGB(0,0,255)) ; SelectObject(hdc, hBrush); Polygon(hdc, arrow2, 7); hBrush = CreateSolidBrush (bFlipFlop ? RGB(255,0,0) : RGB(0,0,255)) ; SelectObject(hdc, hBrush); Polygon(hdc, arrow3, 7); hBrush = CreateSolidBrush (bFlipFlop ? RGB(0,0,255) : RGB(255,0,0)) ; SelectObject(hdc, hBrush); Polygon(hdc, arrow4, 7); DeleteObject (hBrush) ; }
Last edited by Ducky; 11-01-2008 at 03:44 AM.
Using Windows 10 with Code Blocks and MingW.
I personally would put all of the stuff in "variables.h" into a .c or .cpp file (which of those two you choose depends on whether the rest of the project is C or C++). Then you need to put a prototype for paint() into your variables.h (which probably shouldn't have that name, but whatever...)
As to why you are not drawing, I'm fairly confident that you are expecting something different from what you are actually doing. There are several of your initializations that appear to be incorrect - this is the first one:
Now, cxclient is zero when this initialization is done, since your code hasn't started executing properly when the initialization is done (so, what I'm trying to say is that it happens before WinMain - eitner at compile time or as part of the runtime startup, which of those it is doesn't really make much difference, but I presume you are not actually wanting rect2 to have -235, 15, -15, 125 in it, as that would be outside of the visible aree). So when you do InvalidateRect(&rect2), it doesn't invalidate any area of the screen. Likewise when you draw the polygons, they are outside the screen (negative numbers).Code:RECT rect2 = {cxClient -235, 15, cxClient -15, 125} ;
To fix this, you will need to reset your rectangles and arrow values for every WM_SIZE message. I can think of two solutions,
1. Put the values for rect and arrow as constant values, with negative values to indicate that the value should be subtracted from X or Y, and then have two functions, one for rect and one for a list of points, that does the calculation for you (the function should also takes cxclient, cyclient as a parmeter).
2. Have the rect/arrow initializations inside the paint function, and pass cxclient, cyclient to the function (and while you are at it, pass hdc as a parameter as well).
I prefer the first solution, because it is more generic.
Have you actually set up a timer somewhere in your code? I don't see anything that does it [not that it matters right now].
--
Mats
Compilers can produce warnings - make the compiler programmers happy: Use them!
Please don't PM me for help - and no, I don't do help over instant messengers.
Thank you Mats for taking the time to help me.
*me tapping on my forehead*
Of course they are initialized before calling WM_SIZE so they are 0.
I did what you explained in the first version and its not working which is normal because when the InvalidateRect calls get called there is nothing to invalidate.
So if i have to initialize the values in WndProc and in the functions also thats not really a space saver solution i guess.
The best would be if i could call variables.h in WndProc. I dont know if its possible.
Or maybe call a function in WM_TIMER just before InvalidateRect that does nothing only initializes variables.
Well the reason for using a header file is to save place in the .cpp file.Then you need to put a prototype for paint() into your variables.h
So now one line less or more is not really gonna save me any place either, is it?
Yes of course its SetTimer() in WM_CREATE.Have you actually set up a timer somewhere in your code?
PS i never thought a small program would cause so much trouble.
Last edited by Ducky; 11-01-2008 at 10:11 AM.
Using Windows 10 with Code Blocks and MingW.
It is not about saving space - it is about doing things correct and saving you troubles and issues.
They do not need to be put inside the same .cpp file as the rest of the code. You can place it in a .cpp file of its own. Just remember to create a prototype for paint and put it inside a header and include it in the .cpp file that calls the function.
I gotta recheck my protoype knowledge then.
I thought they were to tell WinMain about a function defined later after WinMain in the program.
But since the function is declared in the header file and the header file called "included" in the
beginning of the program i thought you didnt need to declare any prototypes.
Thank you Elysia. Where would we be without you!
Using Windows 10 with Code Blocks and MingW.
Well, theoretically, you are right.
But the problem is that we typically do not define functions in headers (and if we do, we mark them with "inline"), because when working with multiple files, when you include that header in both files, you will get a multiple symbols error from the linker!
So functions are usually put in .cpp files, a prototype is created in a header file.
To call functions, the compiler needs to see a declaration of the function you wish to call (remember that a definition is also a declaration). Therefore, to call a function in another file, you need a prototype.
You can call functions that appears earlier in your code from a function later in the code (in the same file) since it would be defined, but prototypes are still considered good practice!
