There are many ways to compare the popularity of programming languages: number of applications written, lines of code written, number of skilled developers, courses available, communities and tools available, people’s love for the language, number of Google searches, number of online mentions, and more. Check out TIOBE's ranking for May 2020.
TIOBE – updated monthly
"Java and C were already very close in April, but this month C surpasses Java again. The last time C was number one was back in 2015. We can only guess why C is number one again. One of the reasons might be the Corona virus. This might sound silly but some programming languages really benefit from this situation. Examples are Python and R in the data sciences area because everybody is searching for an antidote for the virus. But also embedded software languages such as C and C++ are gaining popularity because these are used in software for medical devices."
- Paul Jansen CEO TIOBE Software
C and C++ are still very much in demand by developers. This is a result of the languages’ heavy use over the years, making them tried and true, and for high-level languages, they offer excellent systems programming support and performance.
Check out IBM's XL C/C++ compiler for z/OS:
https://www.ibm.com/us-en/marketplace/xl-cpp-compiler-zos