Somewhat related to this, printf alone in a loop is Turing-complete, by using %-directives like that. It was introduced in “Control-Flow Bending: On the Effectiveness of Control-Flow Integrity” (Carlini, et al. 2015) and the authors have implemented Brainfuck and an obfuscated tic-tac-toe with it.
[0]: https://nebelwelt.net/publications/files/15SEC.pdf
It does not need the loop. It might be easier to understand by looking at something like this. [0] That printf allows for this kind of Turing complete control flow is well known [1].
https://github.com/HexHive/printbf
well this is a brainfuck interpreter inside printf. I’m pretty sure there are plenty of c-to-bf transpilers.
Reminds me of the turing complete interpreter lurking in libc's printf.