vc++关闭窗口的源代码，关闭前弹出询问确认，弹出一个确认提示框，问询用户是否真的是关闭窗口，确认够简单但实用的小技巧，高手可以路过。-vc++ source code, close the window before the closure of the pop-up asks for a confirmation pop up a confirmation box inquiry whether the user really close the window, to confirm sim