C is the same exact thing as C++ (its the predecessor of C++... its the same but without the Object orientated part).
So, in essence, when you learn C++, you are learning C as well.
I suggest programming in the following order:
C++
Java
C# (a mix between C++ and Java)
Then I would program under Linux to understand the Linux environment. Programming in C++ under linux is a great way to learn networking with programming.