c++ create button
HWND hwndButton = CreateWindow(
L"BUTTON", // Predefined class; Unicode assumed
L"OK", // Button text
WS_TABSTOP | WS_VISIBLE | WS_CHILD | BS_DEFPUSHBUTTON, // Styles
10, // x position
10, // y position
100, // Button width
100, // Button height
m_hwnd, // Parent window
NULL, // No menu.
(HINSTANCE)GetWindowLongPtr(m_hwnd, GWLP_HINSTANCE),
NULL); // Pointer not needed.