小弟我刚学windows编程，模仿书上写了一个，用DEV-C++编译运行的时候不知为什么win窗口后面还有一个DOS窗口，关闭它的话win窗口也会同时关闭
    还有我用visual c++时，编译通过了，没有错误，但是点ctrl+f5执行是会出现两个错误
LIBCD.lib(crt0.obj) : error LNK2001: unresolved external symbol _main
Debug/window.exe : fatal error LNK1120: 1 unresolved externals
Error executing link.exe.

window.exe - 2 error(s), 0 warning(s)
请高手指点下，不胜感激
代码如下：
#include <windows.h>
    LRESULT CALLBACK guocheng(
    HWND hwnd,      // handle to window
    UINT uMsg,      // message identifier
    WPARAM wParam,  // first message parameter
    LPARAM lParam   // second message parameter
    );
int WINAPI WinMain(
  HINSTANCE hInstance,  // handle to current instance
  HINSTANCE hPrevInstance,  // handle to previous instance
  LPSTR lpCmdLine,      // pointer to command line
  int nCmdShow          // show state of window
)
{
    WNDCLASS window;
    window.cbClsExtra=0;
    window.cbWndExtra=0;
    window.hbrBackground=(HBRUSH)GetStockObject(BLACK_BRUSH);
    window.hCursor=LoadCursor(NULL,IDC_APPSTARTING);
    window.hIcon=LoadIcon(NULL,IDI_APPLICATION);
    window.hInstance=hInstance;
    window.lpfnWndProc=guocheng;
    window.lpszClassName="天才";
    window.lpszMenuName=NULL;
    window.style=CS_HREDRAW|CS_VREDRAW;
    RegisterClass(&window);
    HWND hwnd;
    hwnd=CreateWindow("天才","垃圾",WS_OVERLAPPEDWINDOW,CW_USEDEFAULT,CW_USEDEFAULT,
                       CW_USEDEFAULT,CW_USEDEFAULT,NULL,NULL,hInstance,NULL);
    ShowWindow(hwnd,SW_SHOWNORMAL);
    UpdateWindow(hwnd);
    MSG msg;
    while(GetMessage(&msg,NULL,0,0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return 0;
}

    LRESULT CALLBACK guocheng(
    HWND hwnd,      // handle to window
    UINT uMsg,      // message identifier
    WPARAM wParam,  // first message parameter
    LPARAM lParam   // second message parameter
    )
    {
        HDC hdc;
        PAINTSTRUCT ps;
        switch(uMsg)
        {
        case WM_PAINT:
            hdc=BeginPaint(hwnd,&ps);
            EndPaint(hwnd,&ps);
            break;
        case WM_CLOSE:
            if(IDYES==MessageBox(hwnd,"别后悔哦！","退出",MB_YESNO))
            {DestroyWindow(hwnd);
            }
            break;
        case WM_DESTROY:
            PostQuitMessage(0);
            break;
        default:
            return DefWindowProc(hwnd,uMsg,wParam,lParam);

        }
        return 0;
    }