I recommend that you choose one and stick with it long enough to be comfortable with at least its basic features, before starting on the other one. Even though C++ evolved from C, as a sort of "C with object-oriented programming added on", there are significant differences even at the beginning level (i.e. C versus C++ without the object-oriented stuff). You'll probably get confused if you switch between C and C++ books or tutorials.
I used to teach an intro programming course using C++, but it was long enough ago that I'm not familiar with the currently available books etc.
Are you new to programming, or are you already acquainted with some other procedural programming language? (e.g. Python, Fortran, BASIC, Java,...)