Prints randomly generated errors to the console. You can see it in action here: https://problematic.internetpro.me
Compile it like this: g++ -std=c++17 -O3 problematic.cpp -o problematic
It produces a LOT of output very fast (around 130 MiB/s on my machine), so it's best to pipe the output through head or pv -L. I usually run it like so:
./problematic asdf | pv -q -L 300
If you pass at least one argument to problematic, it will use ANSI color codes to denote the different warning levels. It doesn't matter what that argument is.