Dynamic Arrays in C

The presented in the video code is not meant to be production ready. It's meant to convey the main idea of the approach. You actually want to pass xs by pointer and wrap it internally in parenthesis. I've put a better version in a gist:

Just 9 lines of code?

I believe this is how vectors work in C++?

Yes

But creating a new struct for each type! Surely, that makes you an unproductive programmer! /s

this is a nice video format, it's fast but the order of things flows very well

in the macro, what does "do{}while(0)" provide compared to just a pair of curly brackets {...}?