windows窗体程序

自己独立完成的,一运行CPU就100%, 不知道是为什么......

#include  < windows.h >
TCHAR szAppName[ 10 ] = " MyApiWin " ;
LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
BOOL  InitalInstance(HINSTANCE hInstance,HWND hwnd, int  nShowCmd);
BOOL  MyRegisterClass(HINSTANCE  hInstance);
int  WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine,  int  nShowCmd )
{
  HWND  hwnd = NULL;
  MSG msg;
  MyRegisterClass(hInstance);
  InitalInstance(hInstance,hwnd,nShowCmd);
   while  (GetMessage( & msg,NULL, 0 , 0 ))
  {
      DispatchMessageW( & msg);
      TranslateMessage( & msg);
  }
   return  msg.wParam;
}
BOOL  MyRegisterClass(HINSTANCE  hInstance)
{
    WNDCLASS cla;
    cla.cbClsExtra = 0 ;
    cla.cbWndExtra = 0 ;
    cla.hbrBackground = HBRUSH(GetStockObject(WHITE_BRUSH));
    cla.hCursor = LoadCursor(NULL,IDC_ARROW);
    cla.hIcon = LoadIcon(NULL,IDI_APPLICATION);
    cla.hInstance = hInstance;
    cla.lpfnWndProc = WndProc;
    cla.lpszClassName = szAppName;
    cla.lpszMenuName = NULL;
    cla.lpszMenuName = NULL;
    cla.style = CS_HREDRAW | CS_VREDRAW;
     if  ( ! RegisterClass( & cla)){
    MessageBox(NULL,TEXT( " Register Window Failed " ),szAppName,MB_ICONERROR);
     return    false ;}
     else {
         return    true ;}
}
BOOL  InitalInstance(HINSTANCE hInstance,HWND hwnd, int  nShowCmd)
{
    hwnd = CreateWindow(szAppName,
        TEXT( " Hook API Demo " ),
        WS_OVERLAPPEDWINDOW,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        CW_USEDEFAULT,
        NULL,
        NULL,
        hInstance,
        NULL);
    ShowWindow(hwnd,nShowCmd);
    UpdateWindow(hwnd);
     if  ( ! hwnd)
         return   false ;
     else
         return    true ;    
}
LRESULT CALLBACK  WndProc(HWND  hwnd,UINT msg,WPARAM wParam,LPARAM lParam)
{

     switch (msg)
    {
     case  WM_CREATE:
         return    0 ;
     case  WM_PAINT:
         return   0 ;
     case  WM_DESTROY:
        PostQuitMessage( 0 );
         return    0 ;
    }
     return   DefWindowProc(hwnd,msg,wParam,lParam);
}