A brief introduction, create a WIn32 application in vs, I want to register a window class inside, and displayed, but found the second window class registered always fail, please answer

//Win32Project3. CPP: defines the entry point of application, 
//

# include "stdafx. H" 
# include "Win32Project3. H" 

# define MAX_LOADSTRING 100 

//global variables: 
HINSTANCE hInst,//the current instance 
TCHAR szTitle [MAX_LOADSTRING];//title bar text 
TCHAR szWindowClass [MAX_LOADSTRING];//the main window class name 
//this code module contains functions to declare: 
HWND HWND, hWnd1 hWnd2; 
//TCHAR La=TCHAR (" LOVE "); 
TCHAR szname []=TEXT (" classname "); 
The ATOM MyRegisterClass (HINSTANCE HINSTANCE); 
BOOL InitInstance (HINSTANCE, int); 
LRESULT a CALLBACK WndProc1 (HWND, UINT, WPARAM, LPARAM); 
LRESULT a CALLBACK WndProc (HWND, UINT, WPARAM, LPARAM); 
INT_PTR CALLBACK About (HWND, UINT, WPARAM, LPARAM); 

Int APIENTRY _tWinMain (_In_ HINSTANCE HINSTANCE, 

 _In_opt_ HINSTANCE hPrevInstance,_In_ LPTSTR lpCmdLine, 
_In_ int nCmdShow) 
{
UNREFERENCED_PARAMETER (hPrevInstance); 
UNREFERENCED_PARAMETER (lpCmdLine); 

//TODO: placed in the code, 
MSG MSG. 
HACCEL hAccelTable; 

//initialize global string 
LoadString (hInstance, IDS_APP_TITLE, szTitle, MAX_LOADSTRING); 
LoadString (hInstance, IDC_WIN32PROJECT3, szWindowClass, MAX_LOADSTRING); 
MyRegisterClass (hInstance); 

//perform application initialization: 
if (! InitInstance (hInstance, nCmdShow)) 
{
return FALSE; 
} 

HAccelTable=LoadAccelerators (hInstance, MAKEINTRESOURCE (IDC_WIN32PROJECT3)); 

//the main message loop: 
While (GetMessage (& amp; MSG, NULL, 0, 0)) 
{
if (! TranslateAccelerator (MSG. The HWND hAccelTable, & amp; MSG)) 
{
TranslateMessage (& amp; MSG); 
DispatchMessage (& amp; MSG); 
} 
} 

Return (int) MSG. WParam; 
} 



//
//function: MyRegisterClass () 
//
//purpose: registered window class, 
//
The ATOM MyRegisterClass (HINSTANCE HINSTANCE) 
{
Modifed WNDCLASSEX wcex; 


Wcex. CbSize=sizeof (modifed WNDCLASSEX); 

Wcex. Style=CS_HREDRAW | CS_VREDRAW; 
Wcex. LpfnWndProc=WndProc; 
Wcex. CbClsExtra=0; 
Wcex. CbWndExtra=0; 
Wcex. HInstance=hInstance; 
Wcex. HIcon=LoadIcon (hInstance, MAKEINTRESOURCE (IDI_WIN32PROJECT3)); 
Wcex. HCursor=LoadCursor (NULL, IDC_ARROW); 
Wcex. HbrBackground=(HBRUSH) (COLOR_WINDOW + 1); 
Wcex. LpszMenuName=MAKEINTRESOURCE (IDC_WIN32PROJECT3); 
Wcex. LpszClassName=szWindowClass; 
Wcex. HIconSm=LoadIcon (wcex hInstance, MAKEINTRESOURCE (IDI_SMALL)); 
////////////////////////
Wcex. CbSize=sizeof (modifed WNDCLASSEX); 
Modifed WNDCLASSEX wcex2a; 
Wcex2a. Style=CS_HREDRAW | CS_VREDRAW; 
Wcex2a. LpfnWndProc=WndProc1; 
Wcex2a. CbClsExtra=0; 
Wcex2a. CbWndExtra=0; 
Wcex2a. HInstance=hInstance; 
Wcex2a. HIcon=LoadIcon (hInstance, MAKEINTRESOURCE (IDI_WIN32PROJECT3)); 
Wcex2a. HCursor=LoadCursor (NULL, IDC_ARROW); 
Wcex2a. HbrBackground=(HBRUSH) (COLOR_WINDOW + 24); 
Wcex2a. LpszMenuName=MAKEINTRESOURCE (IDC_WIN32PROJECT3); 
Wcex2a. LpszClassName=szname; 
Wcex2a. HIconSm=LoadIcon (wcex hInstance, MAKEINTRESOURCE (IDI_SMALL)); 
if(! RegisterClassEx (& amp; Wcex2a)) 
{
MessageBox (hWnd, L "why?" , "L", MB_OK); 
} 
Return (RegisterClassEx (& amp; Wcex));//& amp; & RegisterClassEx (& amp; Wcex2a)); 
} 

//
//function: InitInstance (HINSTANCE, int) 
//
//purpose: save the instance handle and create the main window 
//
//comment: 
//
//in this function, we save the instance handle in a global variable and 
//create and display the main program window, 
//
BOOL InitInstance (HINSTANCE HINSTANCE, int nCmdShow) 
{
HWND HWND, hWnd1 hWnd2; 

HInst=hInstance;//handle to the instance is stored in the global variable 

HWnd=CreateWindow (szWindowClass, szTitle, WS_OVERLAPPEDWINDOW, 
CW_USEDEFAULT CW_USEDEFAULT, 0, 0, NULL, NULL, hInstance, NULL); 
HWnd1=CreateWindow (szname, L "different class", WS_OVERLAPPEDWINDOW, 
CW_USEDEFAULT CW_USEDEFAULT, 0, 0, NULL, NULL, hInstance, NULL); 
HWnd2=CreateWindow (szWindowClass, L "of" the same class, WS_OVERLAPPEDWINDOW, 
CW_USEDEFAULT CW_USEDEFAULT, 0, 0, NULL, NULL, hInstance, NULL); 
if (! The hWnd | |! HWnd2)//| |! HWnd1) 
{
return FALSE; 
} 

ShowWindow (hWnd, nCmdShow); 
UpdateWindow (hWnd); 
ShowWindow (hWnd1, nCmdShow); 
UpdateWindow (hWnd1); 
ShowWindow (hWnd2, nCmdShow); 
UpdateWindow (hWnd2); 

return TRUE; 
} 

//
//function: WndProc (HWND, UINT, WPARAM, LPARAM) 
//
//purpose: to deal with the news of the main window, 
//
//WM_COMMAND - processing application menu 
//WM_PAINT - draw the main window 
//WM_DESTROY - send out messages and return 
//
//
LRESULT a CALLBACK WndProc (HWND HWND, UINT message, WPARAM WPARAM, LPARAM LPARAM) 
{
Int wmId wmEvent; 
PAINTSTRUCT ps; 
HDC HDC. 

The switch (the message) 
{
Case WM_COMMAND: 
WmId=LOWORD (wParam); 
WmEvent=HIWORD (wParam); 
//analysis menu choice: 
The switch (wmId) 
{
Case IDM_ABOUT: 
DialogBox (hInst, MAKEINTRESOURCE (IDD_ABOUTBOX), hWnd, About); 
break; 
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