I think the third definition here sums up what complex means pretty well: > a group of obviously related units of which the degree and nature of the relationsh

I think the third definition here sums up what complex means pretty well: > a group of obviously related units of which the degree and nature of the relationship is imperfectly known[0] It's impossible for any single person to understand how the C++ language interacts with itself without a reference manual: it's grammar can lead to the most vexing parse; it has metaprogramming builtin using templates or macros, allowing for arbitrary code execution at compile time; it has a ridiculous number of ways to construct an object (move constructors, copy constructors, default constructors, is the object heap or stack allocated, are you using bracket initialization or parenthesis, etc); and more. Also, I pointed this out in a comment awhile ago, but as of C++17 and over 20 years of writing technical books about C++, Scott Meyers doesn't trust himself to determine whether a given code snippet is or is not valid C++: > It's not that I'm too lazy to do it. It's that in order to fix errors, I have to be able to identify them. That's something I no longer trust myself to do.[1] If this language isn't considered complex, I don't know what is. [0]: https://www.merriam-webster.com/dictionary/complex https://www.merriam-webster.com/dictionary/complex [1]: https://scottmeyers.blogspot.com/2018/09/the-errata-evaluation-problem.html?m=1 https://scottmeyers.blogspot.com/2018/09/the-errata-evaluati...