C++ is just C with extra notation for easy modeling of Classes and Objects. While C still remains valuable, C++ is in my opinion questionable and there are many excellent alternatives like Java or C# for doing similar things and much more. I have programmed in C++ for many years and honestly would not suggest it to any one but anyway here are some excellent resources.

ftp://bitsavers.informatik.uni-stuttgart.de/pdf/borland/borland_C++/Borland_C++_Version_2.0_Getting_Started_1991.pdf (Read chapter 4 C++Primer. The hole folder is a rare jewel)

https://docs.microsoft.com/en-us/cpp/cpp/cpp-language-refere... Probably the best documentation of C++ by far.

P.S. If you are desperate on learning C++ I could give short course saving you time and money.