I see pi-e-sigma beat me to it, but: C++ is at least as complicated as Ada, both in terms of using the language and in terms of writing a compiler for it. C++

I see pi-e-sigma beat me to it, but: C++ is at least as complicated as Ada, both in terms of using the language and in terms of writing a compiler for it. C++ also sees plenty of use in military applications. The F-35's 141 page C++ coding standard is publicly available, for instance. https://www.stroustrup.com/JSF-AV-rules.pdf https://www.stroustrup.com/JSF-AV-rules.pdf