Packages

a bundle of one or more crates that provides a set functionality

it contains a cargo.toml file and describes how to build those crates

packages can have as many binary crates as you want but only at most one library crate

packages must have at least one crate

packages are defined by the toml file that comes with creating a new crate

External Packages

These crates are normally found on crates.io in the guessing game the external crate was first defined in the cargo.toml as

rand = "0.8.5"

it was then brough into scope by

use rand::Rng;
// and then used
rand::thread_rng().gen_range(0..=100);

pulling other modules is often the same process

the std library is an external package but it doesn't need to be specified in the toml file

but it does need to be brought into scope with the use keyword

the std::other_part is an absolute path starting with std for the standard library crate