If you are really starting out in the world of programming embedded systems, it is important to be aware that C and C++, although sharing a lot of their genomes, are languages with different purposes.
The 'C' is simplest, and may suffice for most the needs, not incidentally many compilers for microcontrollers are made for this language only.
The C++ in other hand, being a language designed to support object oriented, it is intended to optimize resourses usage on bigest systems which share runtime libraries, but require more hardware resources from the system to do the same job that could be done with C, and for that reason, unless it is really necessary to make use of more a powerful (and complicated) programming language, get started with C.