I have an arduino decimille (a circut board) and it is programmed in C. I sort of learned very basic programming with it but now i need it to input data (the results of an on/off switch) into a database.
What free database programs can i use that will accept input from a program written in C?
You can interface to quite a few different databases with the correct libraries.
Microsoft’s Visual C++ for instance allows binding to Microsoft’s JET engine (used by Access), SQL and a couple of others.
Your best bet will probably be MySQL it has libraries for most OS’s.
mySQL with ODBC