Code:

#include <windows.h>
#include <dde.h>

/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

/*  Make the class name into a global variable  */
char szClassName[ ] = "WindowsApp";

                     
BOOL ProvjeriDalGaIma(char szBr[100])
{
BOOL nadjen=FALSE;
char brojevi[11][10] = {"nula","jedan","dva","tri","cetri","pet","sest","sedam",
                        "osam","devet","deset"};
 for (int x=0;x<=10;x++) if (strcmp(brojevi[x],szBr)==0) nadjen=TRUE;
 if (nadjen==TRUE) return TRUE; else return FALSE;
      
}





int WINAPI WinMain (HINSTANCE hThisInstance,
                    HINSTANCE hPrevInstance,
                    LPSTR lpszArgument,
                    int nFunsterStil)

{
    HWND hwnd;               /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */
  
    /* The Window structure */
    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
    wincl.style = CS_DBLCLKS;                 /* Catch double-clicks */
    wincl.cbSize = sizeof (WNDCLASSEX);

    /* Use default icon and mouse-pointer */
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                 /* No menu */
    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
    wincl.cbWndExtra = 0;                      /* structure or the window instance */
    /* Use Windows's default color as the background of the window */
    wincl.hbrBackground = (HBRUSH) COLOR_BACKGROUND;

    /* Register the window class, and if it fails quit the program */
    if (!RegisterClassEx (&wincl))
        return 0;
        
    /* The class is registered, let's create the program*/
    hwnd = CreateWindowEx (
           0,                   /* Extended possibilites for variation */
           szClassName,         /* Classname */
           "Windows App",       /* Title Text */
           WS_OVERLAPPEDWINDOW, /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           544,                 /* The programs width */
           375,                 /* and height in pixels */
           HWND_DESKTOP,        /* The window is a child-window to desktop */
           NULL,                /* No menu */
           hThisInstance,       /* Program Instance handler */
           NULL                 /* No Window Creation data */
           );

    /* Make the window visible on the screen */
    ShowWindow (hwnd, nFunsterStil);

    /* Run the message loop. It will run until GetMessage() returns 0 */
    while (GetMessage (&messages, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&messages);
        /* Send message to WindowProcedure */
        DispatchMessage(&messages);
    }

    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return messages.wParam;
}


/*  This function is called by the Windows function DispatchMessage()  */

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{ ATOM aApp, aTopic, aItem, aRecvItem, aSentItem; 
  UINT uiLow, uiHi;
  GLOBALHANDLE hDdeAdvise, hDdeData;
  DDEADVISE *pDdeAdvise;
  DDEDATA *pDdeData;
  DDEACK DdeAck;
  WORD wStatus;

  
  char RecvBuff[100], SendBuff[10];
    switch (message)                  /* handle the messages */
    {   
        case WM_DDE_INITIATE:
      
             aApp=GlobalAddAtom("generator");
             aTopic=GlobalAddAtom("brojevi");
             if (LOWORD(lParam)==aApp && HIWORD(lParam)==aTopic)
             SendMessage((HWND)wParam, WM_DDE_ACK, (WPARAM)hwnd, MAKELPARAM(aApp, aTopic));
               else{GlobalDeleteAtom(aApp);
                    GlobalDeleteAtom(aTopic);}

           
             break;
             
    case WM_DDE_ADVISE:
              UnpackDDElParam(WM_DDE_ADVISE, lParam, &uiLow, &uiHi);
              FreeDDElParam(WM_DDE_ADVISE, lParam);
              hDdeAdvise=(GLOBALHANDLE) uiLow;
              pDdeAdvise=(DDEADVISE *) GlobalLock(hDdeAdvise);
                   aRecvItem=(ATOM)uiHi;
                   GlobalGetAtomName(aRecvItem, RecvBuff, sizeof(RecvBuff)); 
                   if (ProvjeriDalGaIma(RecvBuff)==TRUE) 
                        {
                        if (strcmp(RecvBuff,"nula")==0) strcpy(SendBuff,"0");
                        if (strcmp(RecvBuff,"jedan")==0) strcpy(SendBuff,"1");
                        if (strcmp(RecvBuff,"dva")==0) strcpy(SendBuff,"2");
                        if (strcmp(RecvBuff,"tri")==0) strcpy(SendBuff,"3");
                        if (strcmp(RecvBuff,"cetiri")==0) strcpy(SendBuff,"4");
                        if (strcmp(RecvBuff,"pet")==0) strcpy(SendBuff,"5");
                        if (strcmp(RecvBuff,"sest")==0) strcpy(SendBuff,"6");
                        if (strcmp(RecvBuff,"sedam")==0) strcpy(SendBuff,"7");
                        if (strcmp(RecvBuff,"osam")==0) strcpy(SendBuff,"8");
                        if (strcmp(RecvBuff,"devet")==0) strcpy(SendBuff,"9");
                        if (strcmp(RecvBuff,"deset")==0) strcpy(SendBuff,"10");
                        //saljemo WM_DDE_DATA
                        hDdeData=(GLOBALHANDLE) GlobalAlloc(GHND | GMEM_DDESHARE, 
                                                            sizeof(DDEDATA)+strlen(SendBuff)); 
                        pDdeData=(DDEDATA *) GlobalLock(hDdeData);
                        pDdeData->cfFormat=CF_TEXT;
                        if (pDdeAdvise->fAckReq==TRUE) pDdeData->fAckReq=TRUE; else
                                                       pDdeData->fAckReq=FALSE;
                        pDdeData->fResponse=FALSE;
                        pDdeData->fRelease=TRUE;
                        lstrcpy((PSTR)pDdeData->Value, SendBuff);
                        GlobalUnlock(hDdeData);  
                        PostMessage((HWND)wParam, WM_DDE_DATA, (WPARAM)hwnd, PackDDElParam(WM_DDE_DATA,
                                                                                           (UINT)hDdeData,
                                                                                            aRecvItem));
                        GlobalFree(hDdeData);  
                        }        
                    else {
                         //saljemo WM_DDE_ACK jer nemamo trazeni podatak
                         DdeAck.bAppReturnCode=0;
                         DdeAck.reserved=0;
                         DdeAck.fAck=FALSE;
                         DdeAck.fBusy=FALSE;
                         
                         wStatus=*((WORD *)&DdeAck);
                         PostMessage((HWND)wParam, WM_DDE_ACK, (WPARAM)hwnd, PackDDElParam(WM_DDE_ACK,
                                                                                           wStatus,
                                                                                           aRecvItem));
                         }
              GlobalUnlock(hDdeAdvise);
              GlobalFree(hDdeAdvise);
             break;
             
        case WM_DDE_UNADVISE:
             aItem=HIWORD(lParam);
              DdeAck.bAppReturnCode=0;
              DdeAck.reserved=0;
              DdeAck.fAck=FALSE;
              DdeAck.fBusy=FALSE;
                         
             wStatus=*((WORD *)&DdeAck);
             PostMessage((HWND)wParam, WM_DDE_ACK, (WPARAM)hwnd, PackDDElParam(WM_DDE_ACK,
                                                                               wStatus,
                                                                               aItem));
             break; 
        case WM_DDE_TERMINATE:
               PostMessage((HWND)wParam, WM_DDE_TERMINATE, (WPARAM)hwnd, 0L);
             break;
             
        case WM_DESTROY:
            PostQuitMessage (0);       /* send a WM_QUIT to the message queue */
            break;
        default:                      /* for messages that we don't deal with */
            return DefWindowProc (hwnd, message, wParam, lParam);
    }

    return 0;
}