Regard these as long shots.
1. The map file from a debug build will contain a lot of information on the names of variables, functions etc. From that point of view, it may provide a useful list of mental prompts to what was actually there.
2. Check the build directories for listing files. Some compiler options turn on "list" files which show mixed source and assembly code.
3. Check for backup files or files in the trash can.
4. This is extreme and time consuming. Run a disk scanner to do a text search for any sectors which contain text you can remember from your program. The longer you leave this, and the more stuff you write to the disk, the less chance this has of working.
Before you do much more work, create and test a backup procedure, or investigate a source code control system.
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