Day 3 - First Steps

In this article, I discuss how to install Rust and Cargo on macOS, followed by covering some basic concepts of a Rust project, such as its structure and how to build and run a simple "Hello, World!" program. The project setup involves using the `cargo new` command, creating a basic directory structure, and writing a simple `main.rs` file to output "Hello, world!" to the console. Various methods to build and run the program are explored, highlighting `rustc`, `cargo run`, and using an IDE.

In day 2 I forgot to mention how I installed Rust and Cargo since I had them installed some time ago, actually the installation is quite simple just go to the official installation page(https://www.rust-lang.org/tools/install) and follow the instructions. In my case it detected that I was using macOS and it was only necessary to execute the command:

curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh

Now back to the plan. On day 3 I will focus on some basic concepts:

• Structure of a Rust project

• How to build and run

Creating a “Hello, world!”

So, I’ll create the mythic “Hello World” project using the cargo command that is available when Rust is installed:

cargo new hello_world

If everything is ok, an output like this should be shown:

Creating binary (application) `hello_world` package
note: see more `Cargo.toml` keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html

Also a folder with the name of the project will be created, I’ll open that folder on RustRover.

Project Structure

This is the basic structure that is applicable to a wide project types:

my_rust_project/
├── Cargo.toml                         # This is the core configuration
├── src/                               # Main source code
│   ├── main.rs                        # Entry point for binary projects
│   ├── lib.rs                         # Entry point for library projects                          
│   ├─ ...                             # Other files/folders to organize modules
├── tests/                             # Integration tests
├── benches/                           # Benchmarks
├── target/                            # Compiler output
└── .gitignore                         # Git ignore file

Running our “Hello, world”

As this hello_world project is a binary, the code must be on main.rs and is only a function called main with a single statement to print “Hello, world!” on the console.

fn main() {
    println!("Hello, world!");
}

There are few ways to build and run this program:

• rustc

    rustc main.rs #This will genereate a binary
    ./main
  

• cargo

    cargo run main.rs
  

• IDE

  

After running the program, an output like this should be shown:

It may seem basic, but understanding this foundation is key. Next up: making Rust a bit more dynamic. See you on day 4!