MSG msg;
//variable to contain message information
wc.cbsize=sizeof(WNDCLASSEx);
//cbSize should Contain the size of structure itself wc.Style=0;
//Style Specifies the class Style
wc.IpfnWndProc=WndProc;
//WndProc is poniter to wndProc() function wc.cbClsExtra=0;
//Specifies the number of extra butes to allcate following the window_class Structure
wc.cbWndExtra=0;
//Spcifies number of extra butes to allocate following the window instance
wc.hInstance=hInstance;
//Handle to application instance
wc.hIcon=LoadIcon(NULL,IDI_APPLICATION);
//LoadIcon function gives handle to the icon that the int const IDI_APPLICATION represent
//hIcon member of wc refers to the icon Shown when Alt + Tab is pressed.
//First parameter of LOadIcon=Handle to an instance of the module whose executable file contain the icon
// to be loaded. This parameter must be NULL when a standard icon is being loaded.
wc.hCursor=Load Cursor(NULL,IDE_CROSS);