Well I Broke it

I you know those annoying programs that screw up your computer, because they are badly written? Well I made that. My program broke when I resized it to zero height. Lookie:


I'm not sure why it's not working. Luckily I ran it in debug mode. The error was something about a divide by zero. I think it has something to do with the WM_PAINT handler. Here is the code:

[php]//header files to include
#include <windows.h>
#include <stdlib.h>
#include <time.h>

//application title
#define APPTITLE "Hello World"

//function prototypes (forward declarations)
BOOL InitInstance(HINSTANCE,int);
ATOM MyRegisterClass(HINSTANCE);
LRESULT CALLBACK WinProc(HWND,UINT,WPARAM,LPARAM);


//the window event callback function
LRESULT CALLBACK WinProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
PAINTSTRUCT ps;
HDC hdc;
char *szHello = "Hello World!";
RECT rt;
int x, y, n;
COLORREF c;

switch (message)
{
case WM_PAINT:
//get the dimensions of the window
Ge***ientRect(hWnd, &rt);

//start drawing on device context
hdc = BeginPaint(hWnd, &ps);

//draw some text
DrawTextA(hdc, szHello, strlen(szHello), &rt, DT_CENTER);

//draw 1000 random pixels
for (n=0; n<3000; n++)
{
x = rand() % (rt.right - rt.left);
y = rand() % (rt.bottom - rt.top);
c = RGB(rand()%256, rand()%256, rand()%256);
SetPixel(hdc, x, y, c);
}

//stop drawing
EndPaint(hWnd, &ps);
break;

case WM_DESTROY:
PostQuitMessage(0);
break;
}
return DefWindowProcA(hWnd, message, wParam, lParam);
}

//helper function to set up the window properties
ATOM MyRegisterClass(HINSTANCE hInstance)
{
//create the window class structure
WNDCLASSEXA wc;
wc.cbSize = sizeof(WNDCLASSEXA);

//fill the struct with info
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = (WNDPROC)WinProc;
wc.cbClsExtra = 0;
wc.cbWndExtra = 0;
wc.hInstance = hInstance;
wc.hIcon = NULL;
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
wc.lpszMenuName = NULL;
wc.lpszClassName = APPTITLE;
wc.hIconSm = NULL;

//set up the window with the class info
return RegisterClassExA(&wc);
}

//helper function to create the window and refresh it
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
HWND hWnd;

//create a new window
hWnd = CreateWindowA(
APPTITLE, /dow class
APPTITLE, //title bar
WS_OVERLAPPEDWINDOW, /dow style
CW_USEDEFAULT, //x position of window
CW_USEDEFAULT, //y position of window
500, //width of the window
400, //height of the window
NULL, //parent window
NULL, //menu
hInstance, //application instance
NULL); /dow parameters

//was there an error creating the window?
if (!hWnd)
return FALSE;

//display the window
ShowWindow(hWnd, nCmdShow);
UpdateWindow(hWnd);

return TRUE;
}


//entry point for a Windows program
int WINAPI WinMain(HINSTANCE hInstance,
HINSTANCE hPrevInstance,
LPSTR lpCmdLine,
int nCmdShow)
{
// declare variables
MSG msg;

// register the class
MyRegisterClass(hInstance);

// initialize application
if (!InitInstance (hInstance, nCmdShow))
return FALSE;

//set random number seed
srand(time(NULL));

// main message loop
while (GetMessageA(&msg, NULL, 0, 0))
{
TranslateMessage(&msg);
DispatchMessageA(&msg);
}

return msg.wParam;
}[/php]