Game engines are written in c/c++. I've heard that driver software is also written in c/c++ due to the lower-level cababilities of the language. VLC media is written in c from what I've heard. I'd say c/c++ is still the standard in pc programming and software engineering, although Java is also widely used.
The vast majority of infrastructure code is in C++, or a C/C++ mix. The back-bone of most high-level language support structures (libraries, compilers, interpreters, virtual machines, etc.) are written in C/C++. 3D computer games are mostly in C++. Operating systems are mostly a mix of C and C++, that includes both the kernel itself and the low-level tools surrounding it. Most of robotics programming is in C++. Lots of server-side stuff, like web-servers and database engines are written in C++. A very large amount of end-user applications (especially the more complex ones) are written in C++ too, I mean things like Photoshop or MS Office. Also, lots of big-data analytics software and other things like that are often in C++ too.
Basically, for anything that is complex enough, C is too crude and minimalistic. And for anything that is critical in terms of robustness and performance, high-level languages (Java, C#, Python, etc.) simply don't match up to C++. And the area that stands at the intersection of those two things is huge, and it's where C++ is used the most.
C++ may not come out of top in terms of total lines of code in the world (out-ranked by C and Java). In part due to fact that well-written C++ is a lot more terse (fewer lines) than other languages, especially C and Java. But mostly the reason is that C is still huge because of its longer history as the number 1 language, and the existence of lots and lots of legacy C code that people are not just going to throw away because of some preference for a more modern language. And also because some languages that are more directed at end-user applications (Java, C#, Python, etc.), because end-user applications are very numerous, very easy to create, and are often incredibly verbose (therefore enflating the number of lines), and they are also very popular among the hordes of novice programmers. And finally, the area of application that C++ does not cover at all is mainly web-development (even though it often plays a big role in web-infrastructure programs), which is an increasingly big portion of the "market".