小弟出学VC++，写了个创建窗口的程序。可就是有错。

#include <windows.h>

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);
int WINAPI WinMain(HINSTANCE hinstance,HINSTANCE hprevInstance,
   PSTR szCmdLine,int iCmdShow)
{
static TCHAR szAppName[] =TEXT("HelloWin");
HWND hwnd;
MSG msg;
WNDCLASS wndclass;

wndclass.style= CS_HREDRAW|CS_VREDRAW;
wndclass.lpfnWndProc=WndProc;
wndclass.cbClsExtra=0;
wndclass.cbWndExtra=0;
wndclass.hInstance=hinstance;
wndclass.hIcon=LoadIcon(NULL,IDI_APPLICATION);
wndclass.hCursor=LoadCursor(NULL,IDC_ARROW);
wndclass.hbrBackground=(HBRUSH)GetStockObject(WHITE_BRUSH);
wndclass.lpszClassName=szAppName; if(!RegisterClass(&wndclass))
{
MessageBox(NULL,TEXT("This Programme requires Window Nt"),
szAppName, MB_ICONERROR);
return 0;
} hwnd=CreateWindow(szAppName,TEXT("The Hello Programme"),
WS_OVERLAPPEDWINDOW,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
CW_USEDEFAULT,
NULL,
NULL,
hinstance,
NULL); ShowWindow(hwnd,iCmdShow);
UpdateWindow(hwnd); while(GetMessage(&msg,NULL,0,0))
{
TranslateMessage(&msg);
DispatchMessage(&msg);
} return msg.wParam;
}LRESULT CALLBACK WndProc(HWND hwnd,UINT message,WPARAM wParam, LPARAM lParam)
{
HDC hdc;
PAINTSTRUCT ps;
RECT rect; switch(message)
{
// case WM_CREATE:
//PlaySound(TEXT("Hello"),NULL,SND_FILENAME|SND_ASYNC);
// MessageBox(hwnd,'SDFASD','DSFG',32);
// return 0;
case WM_PAINT:
hdc=BeginPaint(hwnd,&ps);
GetClientRect(hwnd,&rect);
DrawText(hdc,TEXT("Hello Windows !"),-1,&rect,
DT_SINGLELINE|DT_CENTER|DT_VCENTER);
EndPaint(hwnd,&ps);
return 0;
case WM_DESTROY:
PostQuitMessage(0);
return 0;
} return DefWindowProc(hwnd,message,wParam,lParam);}下面是错误信息：
Linking...
LIBCD.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
Debug/Cpp2.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.Cpp2.exe - 2 error(s), 0 warning(s)这到底是怎么了？？？
请各位大侠把刀相助！