If you want to program in C, there are ways to implement abstract data types, encapsulation, and implementation hiding that are fairly easy. Basically this involves using the "static" keyword for functions and variables that you want to be private to the implementation and don't put their prototypes/declaration in the .h file you intend for public use. Then you can declare the variables and functions that you want to be public without the "static" keyword and put their prototypes in the public .h file. You can craft the module at whatever level of abstraction/data hiding that you want.
Here is one example http://alastairs-place.net/blog/2013/06/03/encapsulation-in-c/ If you want a higher level language than C (I don't blame you if you do), some people on this list have recently mentioned Go and Rust. -- http://www.fastmail.com - IMAP accessible web-mail
