Вывод из Listbox

#include<Windows.h>
#include<tchar.h>
LRESULT CALLBACK WindowProcedure(HWND, UINT, WPARAM, LPARAM);
HWND hWnd,
lbox;
char szName[] = "window";
int WINAPI WinMain(HINSTANCE hThisInstance, HINSTANCE hPrevInstance, LPSTR lpszArgument, int nFunsterStil)
{
    WNDCLASSEX wincl;
    MSG messages;
    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szName;
    wincl.lpfnWndProc = WindowProcedure;
    wincl.style = CS_DBLCLKS | CS_DROPSHADOW;
    wincl.cbSize = sizeof (WNDCLASSEX);
    wincl.hIcon = LoadIcon(NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon(NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor(NULL, IDC_HAND);
    wincl.lpszMenuName = NULL;
    wincl.cbClsExtra = 0;
    wincl.cbWndExtra = 0;
    wincl.hbrBackground = CreateSolidBrush RGB(204, 204, 204);
    if (!RegisterClassEx(&wincl))
        return 0;
    hWnd = CreateWindowEx(NULL, szName, "Программа", WS_OVERLAPPEDWINDOW, 350, 150, 500, 300, NULL, NULL, NULL, NULL);
    lbox = CreateWindow("LISTBOX", NULL, WS_VISIBLE | WS_CHILD | LBS_SORT, 10, 10, 120, 200, hWnd, NULL, NULL, NULL);
    SendMessage(lbox, LB_ADDSTRING, 0, (LPARAM)"ax^2 + bx + c = 0");
    ShowWindow(hWnd, SW_SHOW);
    while (GetMessage(&messages, hWnd, 0, 0))
    {
        TranslateMessage(&messages);
        DispatchMessage(&messages);
    }
    return messages.wParam;
}
LRESULT CALLBACK WindowProcedure(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message)
    {
    case WM_COMMAND:
 
    default:
        return DefWindowProc(hwnd, message, wParam, lParam);
        break;
    }
    return 0;
}