[win32api] icon

change NULL into hInstance

 char szAppName[] ="해구장"; 
 WndClass.style = NULL; 
 WndClass.lpfnWndProc = WndProc; 
 WndClass.cbClsExtra = 0; 
 WndClass.cbWndExtra = 0; 
 WndClass.hInstance = hInstance; 
 WndClass.hIcon = LoadIcon(hInstance, MAKEINTRESOURCE(IDI_ICON2)); 
 WndClass.hCursor = LoadCursor(NULL, IDC_ARROW); 
 WndClass.hbrBackground = (HBRUSH) GetStockObject(WHITE_BRUSH); 
 WndClass.lpszMenuName = NULL; 
 WndClass.lpszClassName = szAppName;