Python is 0-indexed. In OP's example, the start parameter makes i start at 1.

Their C++17 example prints starting from 0. Probably a mistake.

If you look at the linked page for C++20[0], other types can be put in the initializer statement, so it's unlikely the loop auto-increments.

[0]: https://www.open-std.org/jtc1/sc22/wg21/docs/papers/2017/p06...