workspace: https://www.youtube.com/watch?v=QZKWEEO-Uoo
cargo new --lib --vcs none day02
cargo new --vcs none day01
cargo build -p day01
rustup update -- nightly
rustup default nightly
fn main() {
let foo = 3;
println!("{foo:#?}");
}
:#? is pretty-printed Debug output
:? is normal Debug output
no modifier is Display output
Display is for user-facing output
Debug is for output when debugging, also used for panic messages