As far as your Tax issues are concerned, yes you can take it off your sched C programming-based income.
I have been programming in C since 1977. My college was one of the early users of UNIX. Most of my career was C and then C++ (with random forays into C# and VB and other languages).
Your first step would be the classic Kernighan and Ritchie book "The C Programming Language." There are some good courses on Lynda.com (free).

