saving files unintentionally

Hi, I'm brand new to this editor to resurrect some old C coding from long time ago. (Just starting with it, but I like this editor very much too so far.) I'm finding here that if I accidentally type something into an old file I'm looking at,  and then close the window, it's saving what I typed!!! I want it to be asking to save, not automatically saving. For example here, I closed the window to discard anything I might have accidentally done to it. A global preference setting is needed to "ask to save".  I don't see anything in preferences for this right now.