Be realistic. This is an 8051 forum. Whereas C works pretty well with an 8051, C++ would be difficult to implement efficiently.

So, if you want to use 8051, I would just concentrate on improving your C skills and knowledge.

If you want to improve your job prospects, learn C++ with the ARM Cortex family. There are excellent RealView, GCC, IAR Tools that can build realistic programs on 'giveaway' evaluation boards. And you get the SWD/JTAG debugger too! i.e. you can start for $10-$20

Of course, the 'full-size' Tools cost $1000s, but your employer will happily pay this for a productive C++ programmer.

Other languages exist. You have to choose whether the learning process would enhance your employment prospects.

Good Luck!

David.