A simple windows programm in c
        
The following programm is a minimal windows program. It opens a window and writes a text into the window.
If you compile it with MinGW, be sure to add the -mwindows flag in order to prevent the ... undefined reference to 'TextOutA@20' and ... undefined reference to 'GetStockObject@4 linker error.

#include <windows.h>

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

switch( msg ) {
    case WM_PAINT: {
      PAINTSTRUCT ps;
      HDC hDC = BeginPaint( hWnd, &ps );
      TextOut(hDC, 10, 10, "ADP GmbH", 8 );
      EndPaint( hWnd, &ps );
    }
    break;

case WM_DESTROY:
      PostQuitMessage(0);
    break;

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

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,
                   LPSTR lpCmdLine, int nCmdShow) {

WNDCLASSEX wce;

wce.cbSize        = sizeof(wce);
  wce.style         = CS_VREDRAW | CS_HREDRAW;
  wce.lpfnWndProc   = (WNDPROC) WndProc;
  wce.cbClsExtra    = 0;
  wce.cbWndExtra    = 0;
  wce.hInstance     = hInstance;
  wce.hIcon         = LoadIcon((HINSTANCE) NULL, IDI_APPLICATION);
  wce.hCursor       = LoadCursor((HINSTANCE) NULL, IDC_ARROW);
  wce.hbrBackground = (HBRUSH) GetStockObject(WHITE_BRUSH);
  wce.lpszMenuName  = 0;
  wce.lpszClassName = "ADPWinClass",
  wce.hIconSm       = 0;
 
  if (!RegisterClassEx(&wce)) return 0;
 
  HWND hWnd = CreateWindowEx(
    0,          // Ex Styles
    "ADPWinClass",
    "ADP GmbH",
     WS_OVERLAPPEDWINDOW,
     CW_USEDEFAULT,  // x
     CW_USEDEFAULT,  // y
     CW_USEDEFAULT,  // Height
     CW_USEDEFAULT,  // Width
     NULL,           // Parent Window
     NULL,           // Menu, or windows id if child
     hInstance,      //
     NULL            // Pointer to window specific data
  );

ShowWindow( hWnd, nCmdShow );

MSG msg;
  int r;
  while ((r = GetMessage(&msg, NULL, 0, 0 )) != 0) {
    if (r == -1) {
      ;  // Error!
    }
    else {
      TranslateMessage(&msg);
      DispatchMessage(&msg);
    }
  }

// The application's return value
  return msg.wParam;
};