I've worked with plenty of complex legacy C/C++ :). The downsides are that it doesn't run on modern machines, is difficult to maintain, and you need to impleme

I've worked with plenty of complex legacy C/C++ :). The downsides are that it doesn't run on modern machines, is difficult to maintain, and you need to implement dozens of workarounds to do basic things that can be done in modern languages with just a couple lines of code.