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As a system admin, all you need is Perl.
As a reference to learning 'C' please see Forgetting Syntax. . . in which my learning 'C' in the 80's didn't help much in the late 90's since the 'C' compiler developers didn't think backward compatible was necessary.
Thank goodness, the Perl developers did!
So why not join our group, since you'll learn a lot more about writing real system admin functions on PerlMonks than learning 'C' or 'C++' from a textbook. But then again, I've never found a system admin requirement that I couldn't do with Perl.
"Well done is better than well said." - Benjamin Franklin