it-ebooks - Learning Rust

fn means function. main function is the beginning of every Rust program.
println! prints text to the console and its ! indicate that its a macro instead of a function.

Rust files should have .rs file extension and if youre using more than one word for the file name, follow the snake_case.

compiling via rustc file.rs
executing by ./file on Linux and Mac or file.exe on Windows

These are the other usages of println! macro,

Cargo is Rusts build-in Package Manager. But mainly it uses for,

Create new project : cargo new
Update dependencies : cargo update
Build project : cargo build
Build and run a project : cargo run
Run tests : cargo test
Generate documentation via rustdoc : cargo doc

Other than that there are some cargo commands, especially for publishing crates directly via cargo.

cargo login : acquiring an API token
cargo package : make the local create uploadable to crates.io
cargo publish : make the local create uploadable to crates.io and upload the crate

A crate is a package. Crates can be shared viaCargo.

A crate can produce an executable or a library. In other words, it can be a binary crate or a library crate.

1. cargo new crate_name --bin : produces an executable
2. cargo new crate_name --lib OR cargo new crate_name: produces a library

The first one generates,

and the second one generates,

• Cargo.toml(capital c) is the configuration file which contains all of the metadata that Cargo needs to compile your project.
• src folder is the place to store the source code.
• Each crate has an implicit crate root/ entry point. main.rs is the crate root for a binary crate and lib.rs is the crate root for a library crate.

When we build a binary crate via cargo build or cargo run, the executable file will be stored in target/debug/ folder. But when build it via cargo build --release for a release it will be stored in target/release/ folder.

This is how Cargo Docs describes about the recommended Project Layout,

Source code goes in the src directory.
The default library file is src/lib.rs.
The default executable file is src/main.rs.
Other executables can be placed in src/bin/*.rs.
Integration tests go in the tests directory (unit tests go in each file they're testing).
Examples go in the examples directory.
Benchmarks go in the benches directory.