#include <windows.h>

int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int)
{
  MessageBox(NULL, "Hello World!", "Message", MB_OK);
  return 0;
}

int WINAPI WinMain(HINSTANCE, HINSTANCE, LPSTR, int)

#include <windows.h>
#include <string.h>

const char *CLASSNAME="Tutorial",
           *WINNAME="Tutorial 2 - The Window";

LRESULT CALLBACK WndProc(HWND hWnd, unsigned int iMessage,
                         WPARAM wParam, LPARAM lParam);

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE, LPSTR, int nCmdShow)
{
  HWND hWnd;
  MSG Message;
  WNDCLASS WndClass;
  // NOTE: The memset() here is to avoid this code crashing on
  // WinNT.  (string.h is for memset() function)
  memset(&WndClass, 0, sizeof(WndClass));

  WndClass.cbClsExtra = 0;
  WndClass.cbWndExtra = 0;
  WndClass.hbrBackground = (HBRUSH) GetStockObject(WHITE_BRUSH);
  WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
  WndClass.hIcon = LoadIcon(hInstance, NULL);
  WndClass.hInstance = hInstance;
  WndClass.lpfnWndProc = WndProc;
  WndClass.lpszClassName = CLASSNAME;
  WndClass.style = CS_HREDRAW | CS_VREDRAW;
  if(!RegisterClass(&WndClass))
     return 0;
        
  hWnd = CreateWindow(CLASSNAME, WINNAME, WS_OVERLAPPEDWINDOW,
                      CW_USEDEFAULT, CW_USEDEFAULT, 300, 100,
                      NULL, NULL, hInstance, NULL);

  ShowWindow(hWnd, nCmdShow);
    
  while(GetMessage(&Message, hWnd, 0, 0))
  {
    TranslateMessage(&Message);
    DispatchMessage(&Message);
  }
  return Message.wParam;
}

LRESULT CALLBACK WndProc(HWND hWnd, UINT iMessage, 
                         WPARAM wParam, LPARAM lParam)
{
  switch(iMessage)
  {
  case WM_CLOSE:
  case WM_DESTROY:
    if(MessageBox(hWnd, "Do you really want to quit?",
                  "Message", MB_YESNO) == IDYES)
      PostQuitMessage(0);
    break;
  default:
    return DefWindowProc(hWnd, iMessage, wParam, lParam);
  }
  return 0;
}

  WNDCLASS WndClass;
  // NOTE: memset() is to deal with this code crashing on WinNT
  memset(&WndClass, 0, sizeof(WndClass));

  WndClass.cbClsExtra = 0;
  WndClass.cbWndExtra = 0;
  WndClass.hbrBackground = (HBRUSH) GetStockObject(WHITE_BRUSH);
  WndClass.hCursor = LoadCursor(NULL, IDC_ARROW);
  WndClass.hIcon = LoadIcon(hInstance, NULL);
  WndClass.hInstance = hInstance;
  WndClass.lpfnWndProc = WndProc;
  WndClass.lpszClassName = CLASSNAME;
  WndClass.style = CS_HREDRAW | CS_VREDRAW;

  if(!RegisterClass(&WndClass))
     return 0;

  hWnd = CreateWindow(CLASSNAME, WINNAME, WS_OVERLAPPEDWINDOW,
                      CW_USEDEFAULT, CW_USEDEFAULT, 200, 100,
                      NULL, NULL, hInstance, NULL);

  ShowWindow(hWnd, nCmdShow);

  while(GetMessage(&Message, hWnd, 0, 0))
    {     
      TranslateMessage(&Message);
      DispatchMessage(&Message);
    }
  return Message.wParam;

LRESULT CALLBACK WndProc(HWND hWnd, UINT iMessage, 
                         WPARAM wParam, LPARAM lParam)

{
  switch(iMessage)
  {
  case WM_CLOSE:
    if(MessageBox(hWnd, "Do you really want to quit?",
                  "Message", MB_YESNO) == IDYES)
      PostQuitMessage(0);
    break;

  default:
    return DefWindowProc(hWnd, iMessage, wParam, lParam);
  }
  return 0;
}

HDC hdc;

LRESULT CALLBACK WndProc(HWND hWnd, UINT iMessage,
                         WPARAM wParam, LPARAM lParam)
{
  switch(iMessage)
  {
  case WM_LBUTTONDOWN:
    hdc = GetDC(hWnd);
    if(hdc)
    {
      short xp = LOWORD(lParam);
      short yp = HIWORD(lParam);                        
      MoveToEx(hdc, xp, yp, NULL);
    }
    break;
  case WM_LBUTTONUP:
    if(hdc)
      ReleaseDC(hWnd, hdc);
    hdc = NULL;
    break;
  case WM_MOUSEMOVE:
    if(hdc)
    {
      short xp = LOWORD(lParam);
      short yp = HIWORD(lParam);
      LineTo(hdc, xp, yp);
    }
    break;
  case WM_CLOSE:
    if(MessageBox(hWnd, "Do you really want to quit?",
                  "Message", MB_YESNO) == IDYES)
    {
      if(hdc)
        ReleaseDC(hWnd, hdc);
      PostQuitMessage(0);
    }
    break;
  default:
    return DefWindowProc(hWnd, iMessage, wParam, lParam);
  }
  return 0;
}

case WM_LBUTTONDOWN:
    hdc = GetDC(hWnd);
    if(hdc)
    {
      short xp = LOWORD(lParam);
      short yp = HIWORD(lParam);                        
      MoveToEx(hdc, xp, yp, NULL);
    }
    break;

case WM_LBUTTONUP:
    if(hdc)
      ReleaseDC(hWnd, hdc);
    hdc = NULL;
    break;

 case WM_MOUSEMOVE:
    if(hdc)
    {
      short xp = LOWORD(lParam);
      short yp = HIWORD(lParam);
      LineTo(hdc, xp, yp);
    }
    break;