wc.hbrbackground=(HBRUSH)(COLOR_WINDOW+1);
//Handle to the class background brush.This member can be handle to physical brush to be used for 
//Painting the background or it can be a color value.A color value must be afollowing standard
//system color(value 1 must be added to choosen color)if color value is given,you must convert
//it to HBRUSH type
wc.IpSz Menuname=NULL;
//Pointer to null_terminated character string that specifies the resource nameof class menu
wc.IpSzClassName=g_Sz ClassName;
//our window class name
wc.hIconsm=LoadIcon(NULL,IDI_APPLICATION);
//Handle to icon that is shown in upper_left corrner of application or in the taskbar
if(! Register Class Ex(&wc))
//The Register Class Ex function register a window class for subsequent use in calls to the
create window Ex Function
{
MessageBox(NULL,"This program requires window NT!","Error!",MB_ICONEXCLAMATION MB_OK);
//(handle to owner window,text in message box,message box title,message box style i.e icon & buttons)
//i is a binary or operator
return 0;