新手求教：一个搞不不明白的问题

心中那自由的世界 2004-04-04 08:54:07

我是一个新手，今天碰到一个想不通的问题，以下是Windows程序设计一书中的一例源代码，意为画一条正弦线。小弟我照抄后在VC6.0+win2000环境下编绎可以通过，但是一连接就出现错误：
--------------------Configuration: sinewave - Win32 Debug-----------------
Linking...
LIBCD.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
Debug/sinewave.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.
--------------------------------------------------------------------------
请问这是为什么啊？我真的不明白，郁闷了一个下午。请大虾们指点，小弟先谢过了。

程序代码：

#include <windows.h>
#include <math.h>

#define NUM 1000
#define TWOPI (2.0*3.14159)

LRESULT CALLBACK WndProc(HWND,UINT,WPARAM,LPARAM);

int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPrevInstance,PSTR szCmdline,int iCmdShow)
{
static TCHAR szAppName[]=TEXT("SineWave");
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.lpszMenuName=NULL;
wndclass.lpszClassName=szAppName;
if(!RegisterClass(&wndclass))
{
MessageBox(NULL,TEXT("Program requires Windows NT!"),
szAppName,MB_ICONERROR);
return 0;
}
hwnd=CreateWindow(szAppName,TEXT("Sine Wave Using Polyline"),
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)
{
static int cxClient,cyClient;
HDC hdc;
int i;
PAINTSTRUCT ps;
POINT apt[NUM];

switch(message)
{
case WM_SIZE:
cxClient=LOWORD(lParam);
cyClient=HIWORD(lParam);
return 0;
case WM_PAINT:
hdc=BeginPaint(hwnd,&ps);
MoveToEx(hdc,0,cyClient/2,NULL);
LineTo(hdc,cxClient,cyClient/2);//画直线
for(i=0;i<NUM;i++)
{
apt[i].x=i*cxClient/NUM;
apt[i].y=(int)cyClient/2*(1-sin(TWOPI*i/NUM));
}
Polyline(hdc,apt,NUM);//画正弦线
return 0;
case WM_DESTROY:
PostQuitMessage(0);
return 0;
}
return DefWindowProc(hwnd,message,wParam,lParam);
}

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