C++ is a high-level programming language developed by Bjarne Stroustrup at Bell Labs. C++ adds object-oriented features to its predecessor, C. C++ is one of the most popular programming language for graphical applications, such as those that run in Windows and Macintosh environments.
C++ is one of the most popular languages primarily utilized with system/application software, drivers, client-server applications and embedded firmware.
C++ is used widely throughout many performance critical applications. Games, finance, embedded (think computers inside thermostats, washing-machines, etc.), web applications (GitHub (C, being ported to C++)). The language itself is also constantly evolving. C++ is somewhat unique in that it accommodates most major programming paradigms, without forcing you to use any particular one. Object Oriented Programming, Functional Programming, Literate Programming, etc.
C# is an object-oriented programming language from Microsoft that aims to combine the computing power of C++ with the programming ease of Visual Basic. C# is based on C++ and contains features similar to those of Java.