Change a sybase password from UNIX C/C++ program?

I have to write a password reset utility. The ID and Password will be used by another program and my program will have to be called on a montly basis to change the password.
The ID and Password are stored in a text file. I might have to decrypt and encrypt the file or string, that hasn't been decided yet.
So my prog has to read the ID and password from the text file, log into a given Sybase server, change the password, then write the new PW to the text file.

But should this be done in C? Cant a script just do it?

Regardless is there some Unix lib that facilitates connecting to Sybase? Namely for the purpose of changing an accounts PW?

We have a few scripts and applications around here that change passwords on UNIX servers by using Expect and TCL/TK. Expect actually comes with a password change utility and could be modified to fit your needs...