[remexre]

Because if memory is a big array of bytes and pointers are indices into that big array, that should be numerically valid. And indeed, if instead of making xs and ys separate arrays, one writes:

    int zs[20] = {0};
    int *xs = &zs[0], *ys = &zs[10];

then no perplexing behavior is observed.

Of course, any veteran C programmer will point at that being UB, but the big-array-of-bytes (with holes) model is what one sees in userspace assembly, and what I assume most systems programmers think about most of the time, rather than the C memory model.

I wouldn't recommend that someone trying to learn systems programming (as opposed to C or C++ as languages) spend, like, any time whatsoever memorizing the list of C UBs (and then learning about pointer provenance, exposed addresses, etc., I suppose?). Assembly, Forth, safe Go, and safe Rust don't have the same kind of UB, and (Linux) kernel C has a different set of UBs than userspace/spec-compliant C.

[scoutt]

Why always give the most contort examples? Jeez...

OP is asking about a language to learn. Let them fail, to learn and understand.

And after all, C was and actually is moving the world forward, and thanks to C you have the possibility to write and run programs in Rust. Rust can't do anything if not by calling C APIs. Removing C code from any system is removing the legs from the crab.

So why not choosing C? Seems wise to me. Think about the thousands of lines of C code executing across the world so you can just download a crate. It seems to me that your first interest, as a Rust user, is to have C programmers around so you can run your Rust code.

I'll contribute by telling my personal experience after 20 years of embedded and system C: the fear spread by Rustaceans (regarding UB) is uber-exaggerated, specially at learning stages.

Before you bring exploits up, not every C application is connected to internet or has a user interface or runs as root. Just a portion.