//first parameter =handle to an instance of the module whoes executable file contains the icon to be loaded.
//this parameter must be NULL when a standard icon is being loaded1
//cursor refers to mouse pointer 
wc.hbrBackground=(HBRUSH)(COLOR-window+1);
//handle to the class background  brush .this member can be handle to the physical brush to be used for.
//painting the background,or it can be a color value1a color value must be one of the following standard
//system colors (the value 1 must be added to the chosen color).if a color value is given,you must convert
//it to HBRUSH type
wc.ipszMenuname=NULL;
//pointer to null terminated character string that specifies the resource name of the class menu specifies the resource name of the class Menu.
wc.ipszClassName=q_szClassName;
//our window class name
wc.hIconsm=load Icon(NULL,IDI application);
//handle the icon that is shown in upper_left corner of application or in the taskbar.
//the register classEx function register a window class for subsequent use in calls to the create windowEx function 