Crate library and use local library

---

• Create a library:

cargo new add-lib --lib

The files created:

examples/libraries/add-lib/Cargo.toml

[package]
name = "add-lib"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]

examples/libraries/add-lib/src/lib.rs

pub fn add(left: usize, right: usize) -> usize {
    left + right
}

#[cfg(test)]
mod tests {
    use super::*;

    #[test]
    fn it_works() {
        let result = add(2, 2);
        assert_eq!(result, 4);
    }
}

• Create another crate that will use this library:

cargo new add-app
cd add-app
cargo add --path ../add-lib/

examples/libraries/add-app/Cargo.toml

[package]
name = "add-app"
version = "0.1.0"
edition = "2021"

# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

[dependencies]
add-lib = { version = "0.1.0", path = "../add-lib" }

examples/libraries/add-app/src/main.rs

//cargo add --path ../add-lib/

fn main() {
    println!("Using the add_lib crate: {}", add_lib::add(2, 3));
}