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I've reached the saving part of my game, as in, you press save and it writes to a text file, but I've noticed that most games and programs out there use custom save formats, like Dwarf Fortress DAT files. What are these? are these just text files formatted for the program, or are they a lower level thing?

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Nor does it show any research effort. – Byte56 Apr 3 '12 at 15:13
What you're asking about are called file extensions. Google that. – Byte56 Apr 3 '12 at 15:17
If you want to know what those files are, you should have searched for them directly: a search for PPTX, a search for JPEG, for example. – Josh Petrie Apr 3 '12 at 15:19
@JoshPetrie It wasn't those files I was interested in, it was game save files in general. – Russell Apr 3 '12 at 15:20
I think everyone is attacking @Russell too much. The question may have been worded poorly but the question is still valid. Perhaps "How do you design/implement save files?" would have been a better way of going about it. – Mike C Apr 3 '12 at 16:41
up vote 6 down vote accepted

Many games use a proprietary format for saving data, which they serialize in either plain text or binary form. The format of that data is entirely up to the game, as is the extension the author chooses to use (if one is chosen at all).

That said, all the extensions you've listed probably aren't saved game data at all, because they all have canonical uses elsewhere. PPT and PPTX are usually PointPoint slide decks, JPG and JPEG are image files, and KEY, while less of a de-facto standard, sounds more like a file used to store license key information or something rather than game data.

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.Key is the mac keynote save, I just used it because I couldn't think of game save files of the top of my head (I don't normally play many games) I'll accept this answer after Stack Overflow allows me. – Russell Apr 3 '12 at 15:18

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