Not sure I know what's going on here, and not sure I want to know.
According to cppreference.com, if you use 0 as an integer constant, C considers it to be in octal, not decimal.
I can't wait to talk to a stranger about this at the next party.
https://en.cppreference.com/w/c/language/integer_constant.html
Do we have a plan? No one knows.
[From the NY Times newsletter]
This is an fascinating map, from the Construction Physics newsletter. The population of a core swath of Nebraska, Kansas, Missouri, and Iowa peaked before 1900.