Libraries useful to operate on files - banking system.

Hello guys. I have to write a program imitating a simple banking system working on console. To be honest my only problem are libraries which may be useful, since i want to do this smart. The system should be able to do operations like withdrawal etc. (no problem) and it should save the data like acc numbers, balance etc to a binary file. Operating on file as such shouldn't be a problem (algorithms and so), but i'd like to learn some useful functions / libraries which can help me make it a bit smarter. I know that google doesn't hurt but when i tried to look this up all i got was links to basic operating on files, so no use for me.
I'd really appreciate every help :).

How smart is smart?

This kind of homework normally expects only standard library support (stdio.h, stdlib.h, string.h etc).

Sure, you can make it pretty by using say ncurses, or maybe you fancy adding some sound effects or network capability.

If you want some advice, concentrate on getting the core functionality finished and working. Then use whatever time you have remaining to plan an exercise in making it "better". A pretty program that doesn't work is useless.

I dont think you see what i mean. I dont want to just make it pretty without even knowing what im doing. I can make it using simple functions, but i dont want to invent the wheel all over again. Besides that i want to know more libraries better. And yeah, im sure sound effects in console application are very usefull, but i just want to know how to make it properly.

I can't see how you need much more than fopen/fclose/fread/fwrite/qsort and the usual printf/scanf

I'm sure you could contrive the need to use say strcspn(), setjmp() or signal() but why?

You're not going to achieve "how to make it properly" by doing so. Unless the problem actually calls for those functions, you just end up with a contrived mess.