Can't see my first window application - c++

Question

I was working through a book which shows me how to create a windows application. I have written the code, however when I compile and run it, it says that it was successfuly built but it doesn't show a window where it should write "Hello World". I am using Visual Studio 2010 with C++, what might be the problem?
Thanks
Here is the code;
//Header Files
#include <windows.h>
#include <stdlib.h>
#include <time.h>
//Application Title
#define APPTITLE L"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
GetClientRect( hWnd, &rt);
//Start drawing on device context
hdc = BeginPaint( hWnd, &ps);
//Draw some text
DrawText( hdc, L"Hello World!", strlen( "Hello World!"), &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 DefWindowProc(hWnd, message, wParam, lParam);
}
//helper function to set up the window properties
ATOM MyRegisterClass(HINSTANCE hInstance)
{
//create the window class structure
WNDCLASSEX wc;
wc.cbSize = sizeof( WNDCLASSEX);
//FILL THE STRUCT WITH INGO
wc.cbSize = 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(WHITE_BRUSH);
wc.lpszMenuName = NULL;
wc.lpszClassName = APPTITLE;
wc.hIconSm = NULL;
//set up the window with the class info
return RegisterClassEx(&wc);
}
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
HWND hWnd;
//create a new window
hWnd = CreateWindow(
APPTITLE, //Window class
APPTITLE, //title bar
WS_OVERLAPPEDWINDOW, //window Style
CW_USEDEFAULT, //x position of window
CW_USEDEFAULT, //y postion of window
500, //width of the window
400, //height of the window
NULL, //parent window
NULL, //menu
hInstance, //application instance
NULL); //window 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 varuables
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( GetMessage(&msg, NULL, 0, 0))
{
TranslateMessage( &msg);
DispatchMessage( &msg);
}
return msg.wParam;
}

Answer 1

This line is wrong:
wc.cbSize = CS_HREDRAW | CS_VREDRAW;
You mean
wc.style = CS_HREDRAW | CS_VREDRAW;
In fact I would change the window class initialisation code so that you make it very clear in the code that the entire struct is initialised.
WNDCLASSEX wc = { 0 };//initialise struct to 0
wc.cbSize = sizeof( WNDCLASSEX);
//FILL THE STRUCT WITH INGO
wc.style = CS_HREDRAW | CS_VREDRAW;
wc.lpfnWndProc = (WNDPROC)WinProc;
wc.hInstance = hInstance;
wc.hCursor = LoadCursor(NULL, IDC_ARROW);
wc.hbrBackground = (HBRUSH)GetStockObject(WHITE_BRUSH);
wc.lpszClassName = APPTITLE;
And you were missing some error checking:
if (!MyRegisterClass( hInstance))
return FALSE;
Stepping through under the debugger will allow you to see where in the process things are going wrong.