win32编程序定义父窗口类和子窗口类，出现问题，求解呀！！

用win32编写程序，想创建子窗口和父窗口，首先设计个窗口类，我用WNDCLASS定义两个窗口类wndclass和childwndclass，为什么编译的时候老是报错，
d:\pci9846h\sdk98x6dbfposttrg\98x6ptrg.c(201) : error C2275: 'WNDCLASS' : illegal use of this type as an expression
        c:\program files\microsoft visual studio\vc98\include\winuser.h(1214) : see declaration of 'WNDCLASS'
d:\pci9846h\sdk98x6dbfposttrg\98x6ptrg.c(201) : error C2146: syntax error : missing ';' before identifier 'childwndclass'
d:\pci9846h\sdk98x6dbfposttrg\98x6ptrg.c(201) : error C2065: 'childwndclass' : undeclared identifier
d:\pci9846h\sdk98x6dbfposttrg\98x6ptrg.c(202) : error C2224: left of '.style' must have struct/union type
d:\pci9846h\sdk98x6dbfposttrg\98x6ptrg.c(203) : error C2224: left of '.lpfnWndProc' must have struct/union type
d:\pci9846h\sdk98x6dbfposttrg\98x6ptrg.c(204) : error C2224: left of '.cbClsExtra' must have struct/union type
我看《windows程序设计》书上第七章鼠标里面的checker3程序，它是只用WNDCLASS定义一个wndclass表示父窗口类和子窗口类。
不知道定义两个窗口类名为什么报错？